I used to think it was some MS anti-competition BS, and it's had some atrocious PR (from Phil Spencer included).
But then I read up on what it actually was. It's to stop devs getting free dev kits for a port of a game they've released on all other platforms already, UNLESS they can prove it was impossible for them in terms of finances and manpower to release on Xbox 1 at the same time as other platforms.
Nothing really restrictive, it's mainly to stop abuse by some devs.
Imo ID@Xbox is in a fairly good place atm, but the program and it's games need better discoverability and promotion, that's where Sony and PS4 in paticular have the edge still. And ID@Xbox could do with one massive title like No Man's Sky, WiLD ,etc.
Also worth mentioning is Game Preview, which shows promise, mainly because of the mandatory free trial which should act as a crap filter.The lowest price guarantee is great as well. However it has yet to build on the two games it initially offered, so we'll have to wait and see on that one.
PS, PS2, Gameboy Advance, PS3, PSP, PS4, Xbox One







