Now that Lexus has upgraded the horsepower to 303 the equation may have changed. My lease is about to expire on my'03 Audi A6 2,7T w/ quattro and the main prerequisite for my next car is AWD. I have narrowed it down to the GS350 and the M35X and have test driven both of them. The Lexus is now quicker off the line and in passing situations than the M. The M handles better as best as I could tell since the test run in the Lexus was on straight roads in traffic. The Lexus is quieter, more refined and more luxurious feeling but the M is sportier and more fun to drive. The M steering has more feedback and the Lexus steering feels somewhat disconnected in comparison.The Lexus is smaller inside and has a tiny trunk. It appears that the technology in the M is better somewhat. The M doesn't have automatic door locking which I like and in order to get HID headlights you need to order the advanced tech package( which has features I don't want) and then add on another $800 for the lights. The Infiniti dealerships are more high pressure and the Lexus dealerships are far classier however I have no idea who has better service.
Now that the Lexus has upped the hp I'm curious to hear opinions on preferences. I change my mind every day.