Kia has done us the favor of providing complete mpg numbers for every K5 trim except the flagship GT. The entry-level K5 LX with front-wheel drive gets 29 miles per gallon in the city, 38 on the highway, and 32 combined. This lines up with a model on the EPA site that's listed with stop/start on the 1.6-liter turbocharged four-cylinder. Most notably, the K5 LX sips a lot less fuel than the entry-level 2020 Kia Optima LX. The Optima LX houses a 2.4-liter four-cylinder with 185 horsepower and 178 pound-feet of torque — five horses up but 12 lb-ft down on the K5 — and gets 24 city, 32 highway, 27 combined. And the K5 only costs $100 more than the Optima.

Among the competitive set, the in-house rival Hyundai Sonata in entry-level SE trim gives up one mile per gallon in the city to the LX, otherwise the two are equal. The Sonata SE, though, gets motivated by a 2.5-liter four-cylinder with 191 hp and 181 lb-ft. The Sonata SEL Plus with the same 1.6-liter as the Kia but costing $4,000 more returns 27 city, 36 highway, 31 combined. Outside the fold, the Toyota Camry ultimately evens out the fuel economy score in delivering 28 mpg city, 39 highway, 32 combined. The Honda Accord edges all comers with 30 mpg city, 38 mpg highway, and 33 combined thanks to its continuously variable transmission; the other three shift through eight-speed automatics.

The front-wheel drive K5 LXS, EX, and GT-Line all return 27 mpg city, 37 mpg highway, and 31 mpg combined. The figures match a K5 model on the EPA site that omits the stop/start system on the 1.6-liter, but we can't see where Kia has mentioned a stop/start system in its K5 release materials. About 100 pounds difference in curb weight covers all four trims that we have info on so far. This would appear to indicate the lack of the fuel-saving tech on the three trims causing slightly lower fuel economy as opposed to extra luxuries weighing matters down.

Only two trims for now come with the option of all-wheel drive, the LXS and GT-Line. When the K5 GT arrives, it will only come with all-wheel drive. Check the box to send power to all the wheels, and both variants deliver 26 mpg city, 34 mpg highway, 29 mpg combined. The Camry SE AWD comes closest to the LXS, mustering 25 city, 34 highway, and 29 combined, whereas the higher-trim XSE cuts combined mileage to 28 mpg. Among the other AWD entries in the segment at this price range, the Nissan Altima S AWD gets 26 city, 36 highway, 30 combined, the Subaru Legacy AWD with the naturally aspirated 2.5-liter returns 27 city, 35 highway, and 30 combined, both of those options shifting through CVTs.

Despite the sedan market continuing to lose market share to crossovers and SUVs every year, it’s still a segment that sells millions of units a year. It’s also one of the most hotly contested segments with strong offerings from Honda, Toyota and Mazda among others, which means it’s hard to stand out. But the 2021 Kia K5 aims to do exactly that. It discards the long-running Optima nameplate for the model's Korean-market alphanumeric designation, and adopts the most dramatic styling Kia has ever used on a midsize sedan. Kia has coupled that with a stylish, quality interior, and a driving experience that is exceedingly comfortable. It's not particularly engaging to drive, which prevents it from being the segment's best, but it’s a strong competitor that’s worth your consideration.

Like the K5’s Optima predecessor, the K5 is mechanically related to the Hyundai Sonata, and shares powertrains with it. But this time, it’s a bit choosier. The only engine available at launch is a 1.6-liter turbocharged four-cylinder making 180 horsepower and 195 pound-feet of torque coupled to an eight-speed automatic transmission. The Sonata's naturally aspirated four-cylinder is nowhere to be found. Fuel economy comes in at 27 mpg city, 37 mpg highway and 31 mpg combined for most trim levels, with the base LX basically getting 1 mpg better.

The K5 will also offer all-wheel drive with this engine, again differing from the Hyundai. Later this year, a much more powerful 290-hp turbocharged 2.0-liter engine shared with the Sonata N-Line will be offered on the K5 GT. This version will be front-wheel-drive-only and get an eight-speed dual-clutch automatic instead of a traditional torque-converter unit. Kia is promising a 0-60 time of 5.8 seconds, which would be blisteringly quick for a family sedan.

In the EX and GT-Line models we tested out, we found the standard engine had plenty of torque throughout the rev band, so it will comfortably haul you around, but never really excite. It’s mostly quiet, but pushing it hard will elicit some buzziness. The transmission is quite smooth and chooses gears well enough, but gear changes in manual mode are sluggish. Again, we’re hoping the GT will liven things up a bit.

Not being exciting is not necessarily a bad thing, though. It won’t be long before you discover that the K5’s advantage is its superb comfort. The suspension is soft and supple, easing you along broken pavement while not feeling disconnected and wallowy. With a quiet cabin and powertrain, the K5 would be an excellent long-distance cruiser or serene commuter.

Should you be looking for less serenity and more excitement, though, the K5 is unlikely to deliver despite its strengthened body and revised suspension geometry compared to the Optima. The steering is weighty and resistance builds naturally and progressively, but it also isn't as sensitive and precise as what you'll get in a Honda Accord or Mazda6. There’s moderate body roll, and the chassis is slow to react to changes in direction. It also doesn’t have much grip, and with common suspension tuning throughout the trim lineup, it's not like one K5 is zippier than another. At least yet. We expect the full GT trim to improve the handling.

So, the K5’s driving experience may not excite, but the exterior and interior sure do. The scowling headlights, fierce, forward-leaning grille and undulating hood give it attitude that’s lacking in the midsize segment. The front fascia blends into organic and athletic flanks on the way to a vented and diffuser-laden tail with a stylish full-width taillight unit. This generally applies to both the GT-Line and the regular K5, too. The GT-Line gets more aggressive grille mesh, a more distinct diffuser, quad exhaust tips and a spoiler, whereas other K5s get some extra chrome trim and integrated exhaust.

Step inside the K5 and things are just as good, if not quite as bold. Each part of the dual-level dash is split up by either some textured plastic or nice faux wood trim. The air vents and other trim have a stylish aluminum look, and the larger swathes of plastic are high quality, soft-touch pieces.

Finding a comfortable driving position is easy thanks to the highly adjustable steering wheel and seat sliders common in Kia and Hyundai vehicles. The K5’s seats are also impressively comfortable with thick, soft cushions and enough bolstering that it feels like it’s giving you a gentle hug. People comfortable with crossovers will find the slightly tall seating position welcoming. The rear seats aren’t quite as comfortable but are still pleasant enough, and there’s plenty of legroom. Headroom is a touch tight, though. That should probably not be surprising since the K5's overall height is lower by nearly an inch compared to the Optima, which hardly had a tall greenhouse. Elsewhere, however, the K5 grows compared to its predecessor: 2 inches longer overall, 1.8 inches longer wheelbase and 1 inch wider. Cargo volume is also up a tiny bit and is at the larger end of the spectrum with 16 cubic feet, topping the Toyota Camry’s 15.1 and Nissan Altima’s 15.4, whereas the Honda Accord has more with 16.7 cubic feet.

All K5s come standard with an 8-inch infotainment screen, and it uses the same operating system that has appeared in all Kias and Hyundais the past few years. As such, it’s starting to look a little old, but still runs well with clear, simple menus and buttons, and quick responses. The screen is surrounded by familiar shortcut buttons and volume and tuning *****. Available is a 10.25-inch widescreen unit that further improves usability while adding prettier graphics and an updated version of Kia's UI software. Its removal of a tuning **** and addition of touch-sensitive "buttons" in place of physical ones is unfortunate, though.

This stylish and comfy midsize sedan is also competitively priced, sliding in below the segment’s best-selling Honda Accord and Toyota Camry. The base K5 LX starts at $24,455, which means it starts about $500 less than the base Accord and about $900 below the base Camry. Some of the major standard features included on this base K5 are 16-inch alloy wheels, heated mirrors, dual-zone automatic climate control, an 8-inch touchscreen, wireless Android Auto and Apple CarPlay, automatic emergency braking with pedestrian detection, lane-keeping assist, driver inattention warning and automatic high-beam headlights.

The K5 even maintains a price advantage all the way up to the EX trim level, while the high-output K5 GT will undercut the comparable 2.0-liter Honda Accord and V6 Toyota Camry by a few hundred dollars when it goes on sale this fall.

The Kia K5 ultimately seems unlikely to take home the prize in a comparison test since its handling doesn’t quite match that of the spectacularly well-rounded Honda Accord. But it delivers in other important areas that midsize buyers care about. It has muscular good looks, a classy interior and is cosseting on the road. And it all comes in at a strong price point. It’s must-see for any prospective midsize buyer.