I voted mixed, i've disliked vehicles for quite some time. I just prefer the pace of an IO map, admitted, i enjoy(ed) choppers but only when i was allowed to seat switch. Anyhew, i'd choose IO over conquest any day now.
There are far more things i detest about conquest compared to IO. To name a few: getting spawn raped by a tank/chopper, artillery, vehicle whores and the outright bias for a team on certain maps (see Sharqui and MEC for one).
Whereas with IO at least its a more even playing field and imo, skill shines more on IO. A downside being nade spamming but that was prevelant long before IO. But my biggest vitriol for IO is commander and skill-o UAV, what is the fucking point!