It's being demoed on PS3, which seems to indicate that the PS3 is the lead platform. Sony also announced a partnership with R* that will likely lead to more than just the headphone bundle.
Also I'm not going to renew my Live subscription. F that.
Core i5 2500K @ 4.8 GHz || 16 GBs 1600 MHz DDR3 || Sapphire Radeon HD 7970 || Dual 128 GB SSDs