2014 S550 as well? If so, with warranty being equal between the two, as long as you don't have any intention of owning either outside of warranty, S550 without a doubt. Intending on owning past warranty? Get the LS.

 

 

I wouldn't own either of these without an extended warranty. Can't compare S550 against LS460, MB is leaps and bound ahead of Lexus when it comes to technology. Believe it or not, when I was in the market searching for LS600, I did find few of those even without ML audio !. Even all LS600 ($120k) doesn't equipped with LKA. I understand many of these are (especially LS600) are custom ordered, still I would expect Lexus to maintain certain features as standard.

I was heavily depending on 2018 LS to compete against MB S series but disappointed. Most likely my next one would be S. MB service and parts would be more expensive than Lexus.

Attaching CR report on 2014 S550.

 

 

 

S550 over an LS460.
I'd take another G90 over both, but that wasn't an option

 

As others have mentioned the S-class is the superior car when it comes to driving dynamics and technology. I deal in german cars, mostly BMWs, but have plenty of wrench time on Mercs. The reliability of SOME components isn't there long term. Each chassis always seems to have some shortcomings so you'll have to see where the W222 falls short. I love german cars and collect many of them, however I daily drive an LS. I'm not going to say I love the LS, but I respect it for what it is. A very durable, comfortable luxury car. I've owned all manner of european cars and grow tired of constantly fixing them- and I buy parts and do my own labor. At $120 per hour if you don't DIY it's even more tiresome. I'll happily deal with the collectors, but the daily driver I depend on, no thanks.
You can find a S550 with a certified warranty from the dealer and a manufacturer's warranty is always preferred over a third party. I'm sure there are some good third party warranties out there, but many are very shady operations that sound good upfront but turn into a headache quickly when you try to make a claim. BTW, they're called "service contracts" now so they can bypass all the warranty laws.
Here on the LS forum everyone is going to tell you to buy the LS for reliability, over on the S-Class forum everyone will call the LS boring. You just have to decide what characteristics you want out of your car.

 

One other thing to keep in mind, and you'll see this when you look at them used. They don't age like the LS, the same is true of the 7 Series. Cupholder covers creak when they open or grind, little things like that when you sit in one with say 40k miles and then you sit in an LS with 40k miles, theres a difference there.

 

Ive been reading the forums over there, and there are tons of complaints of creaks and rattles. They also seem to accept the issues that come up and pay for them to experience the ride and features of the car. I'm way off from grabbing something, but I have been looking around. Took me over 6 months to buy the first 460.

 

And quite frankly, the ride and drive is not THAT different than a LWB air suspension LS460L. I drove it back to back with my SWB coil sprung LS460 and the difference with that wasn't enormous. Noise isolation, etc is very similar.

 

My wife got her 2014 LS in October of '15; her friend picked up her '13 S550 a few months later. Both are nice cars. Neither my wife or her friend have scratched the surface on the features of their cars and how to use them (her friend's S550, of course, has a lot longer list of stuff).

Original sticker price is meaningless but the MB started a lot higher but fell off quickly in the used market. As far as I know, her friends MB has been reliable. Other than oil changes and recent tires, the wife's LS460 has been stellar.

I think it is a coin toss..... Base your decision on how long you plan to own them (as others have pointed out....).

 

The 13 S550 and the 14 S550 are different animals altogether. If the OP were asking about a 13 S550 I would say easily get the LS460.