Both sides (PS3 / 360) have advantages and disadvantages that could even out the amount of sales for each consoles.
360 PROs - bigger userbase, most affordable console, and DL content
PS3 PROs - bigger FANbase, franchise is more well-known on a PS console
360 CONs - PAYED to have content in first place, HW unreliable
PS3 CONs - console less affordable, no DL content, and smaller userbase
If there is anything else or if I'm wrong then please add!
Generation 8 Predictions so far.....(as of 9/2013)
Console that will sell most: Nintendo Wii U
Who will sell more consoles between Microsoft/SONY: SONY