Street Fighter IV has already been released on Consoles and is doing great! The PC version however is scheduled for summer and according to Seth Killian it will come with some extra.
Here is what Seth Killian had to say: "SFIV PC has a little un-discussed juice yet to reveal--stay tuned. "
I wonder what the extra juice will be? Dee Jay and t-hawk? extra stages? something else? Time will tell
source: Capcom Unity