The 4 cyl had fewer problems because the engine developed less torque. Honda fixed the major problems in 2005, but the transmissions are still pretty weak compared to other manufacturers. Best combo is the 4 cyl with MT. The 2006 V6 AT and later has stability control, the 4 cyl got ESC in 2008.
Even with the transmission fix it is a good idea to follow the severe service schedule with those transmissions.
The V6 engines require a major service around 100K : timing belt, water pump, tensioner, etc.. plus the usual drive belt and iridium plugs. Depending on where you live that would cost $700-$1000 above and beyond the 4 cyl which use a permanent timing chain.
In addition, the V6 cars have more suspension issues. This may not be an issue for you on smooth roads.