$500 seems a bit just much to enable playing Forza 5, IMO. BF4 will be on pretty much everything... XBox 360. XBox One, PS3, PS4, and PC, and when PC is an option... well, there's the best choice in 98% of cases.
I have somewhat limited experience with the xbox though, so I don't know what's so unique about the "xbox live experience" to make it a significant factor over the redesigned PSN or PC gaming?