Very successful. I keep all my old consoles, having the BC feature isn't a deal breaker either way for me. But damn, i would love to have real BC on my PS4. It would just be nice to have.
I think Microsoft is really gaining the faith back from gamers with things like BC. It shows that their 'nobody left behind' motto is the future. You should be able to play your entire gaming library on one box. Technology should always be two steps forward, without the one step back.
Was happy to see that Gears of War 3 was a pre-order reward for ordering Gears 4. Have been trying to play it - it has locked up on me six times and I'm still on the opening fight on the deck of the ship - locks up the whole Xbox and have to do a hard manual reset each time.