We purchased our 2012 Civic LX Sedan in Dec. 2011 as a commuter car and have put about 17K miles on it. Like most have mentioned, the road noise is present and the sound system is not up to par.
My biggest complaint is the shifter/transmission (auto) tends to vibrate while accelerating quickly. Pulling out in traffic can be a bit dangerous too, if you forget the ECON button is on.
That being said, overall, my wife and I are very satisfied with our Civic.
The legroom is plentiful for this size car. The fuel economy is great (~32 in City). And the displays are very easily read.
Base features are good (USB/AUX, PWR everything except seats, digital speedometer)
Fuel economy is very good.
Leg room is great for this size car.
Better sound system for LX.
Better performance for merging.
Take care of the rattle in the shifter.
Upgrade the carpet and sound-deadening matterials.
USB is temperamental.
Use wider tires for a smoother ride.