I have nothing against the 360 but I'm not going to pay for a service just for online play, not as long as I can get it free on PC or other consoles. That was one of the reasons I went with the PS3 this generation. After being a PC gamer only for a few years, I evaluated them both, and that was one of the factors that influenced my decision. It just doesn't sit very well with me.
If the 720 is the same, unless it offers something new and spectacular, then I will probably count that as a negative. They would have to add value, as the OP suggests, in one way or another. As I don't really care much about Netflix or streaming on a console, it would have to be something closer to Sony's PS+, where you get a selection of several games a month at no extra charge.
