Always been a PS for me, however I did look into Xbox before I bought my PS3, done a bit research and mainly there are not a lot difference. Actual choice was actually based on games, as u know some games only made for PS or XBox...and I guess many people decide on that as well, if u like kill zone or GOW etc etc etc
Plus PSN is free, which is bonus and never had any issues yet!
As of PS4 or XBox One... Ill stick to PS3 for now and spend £300-£400 on Z instead lol