Ive done my fair share of research...
Currently own a RSX-S and ive been looking to trade in for a TL or TSX...
With the TSX you dont have much to worry about, there arent any 'hidden' problems with the car
Check out consumerguide.com for a full review (and reliablity/repair costs)
Also.. Check out fueleconomy.gov for some mileage information (you will find the TSX to be very good here too)
Its a great car for the price, you cant go wrong