As a former Acura TL, and Lexus ES 300 owner, I can say that this car meets and in most cases exceeds my previous ownership experiences with either of these vehicles. The quality of this car is outstanding. By all means get the CXS, the larger engine completes the package. My wife has a new Lexus RX 350 and the CXS is far superior in terms of quality of materials on the interior, the NAV system (she has already complained to Lexus), and many amenities she doesn't have on her vehicle (heads up display, heated steering wheel, ambient lighting, remote start, 5.1 surround sound, etc.) 2000 miles so far and the car is perfect. 25.5 MPG at 74 MPH.
Ride quality (not as harsh as the TL, but not as marshmallow soft as the ES 300 -- good road feel but comfortable, NAV system (ease of use, graphics clarity, way its tied in to the heads up display), sumptuous interior, ambient lighting, 5.1 surround sound, eye catching looks.
Slightly larger trunk. Front pillars are noticeable, but you adjust to them.