After having an LS, I wouldn't want to sacrafice the ride and comfort. The IS would feel slow to me anyway, so my vote goes to the LS.

 

This is my first post on club Lexus. I just found the site when I purchased my new IS from a broker.( he told me about it) So now I have already hacked my bluetooth and my ML video system, piece of cake thanks to the info on this site.
I got my 04 Ls 430 Sport suspension,nav/ML, 12/03, 28000 miles now. Lota dough, don't regret it. Nothing else would do. Smooth,fast,quiet,no complaints. By the way I just turned 45yrs old.
The NEW IS comes out, become obsessed, red one FULLY loaded shows up on ebay in Arkansas, $1000 below MSRP(buy it now) of like $47900 list. I just couldn't help myself click, click, click, I get it for $46200. Off I go to pick it up drive it back. AWESOME radar cruise, windows all ready done with the platinum tint, every option available except g spiders and spoiler.
I'm finding it hard to drive the LS because the IS is so cool and fun to drive. My sore back likes the seat in the IS better. I really like the cockpit feel of the IS as opposed to the big spread of the LS. I've only driven it less than 3000 miles, but I have pushed on a few mountain roads and what a kick, makes me feel like a real race car driver pitching it a little sideways with the computer right there to back me up.
The IS really is an real eye catcher, with the red the tint 18'' wheels.....OH YEA!!
OOPs sorry got carried away there. Hope that helps.