Microsoft pioneered one great thing with the Xbox, Party Chat, that in itself was brilliant, especially with people in different games. Xbox also came out first with the achievements, as you saw with the early PS3, games were not required to have trophies. When they saw how well Achievements worked in games, Sony ripped them off, much like Steam has. For some reason, Nintendo has not done this, and they still won Generation 7 in both handheld and console, although their legs ran out in the Wii 2 years ago, and NOT because of the Move or Kinect, because of the quality of third party games(IE, the Wii had significantly less)
The Playstation 3 had a Blu Ray player, that's huge because there's no disc swapping, even if you don't play video games, you can use it as a blu ray player and a place to store movies, pictures, etc. The graphics on the system were a little more detailed. Play Battlefield 3 and you'll see a difference.
If Microsoft did not charge for it's online service, they would've dominated the 7th generation, that is a major turnoff especially when Playstation Plus offered so many free games over the course of 3 years, this strategy proved to be more successful than charging for online, causing some people to defect to Sony, or actually give up their PS2's in favor of a PS3.
The only downside to the Wii U releasing a system now, instead of 1-2 years from now, Microsoft and Sony can rip off the gamepad ideas before even thinking about releasing their system, and find ways to beat Nintendo. Add to that, there are 4K resolution TV's, Wii U might run into the same problem with games not supporting 3840x2160 resolution, whereas the Xbox 720 and PS4 are expected to. Wii had 480p, Xbox and PS3 had 1080, hell even the PS2 had 720p in some games. But in honestly, that's not as crippling as 4:3 versus 16:9 resolution, unless PS4 finds a way to implement Simulview technology and 3D in ALL of their games, which would be a HUGE draw, imagine 6 people playing the same game, all in full screen, tied to your pair of 3D glasses. Now that would be groundbreaking.
Imagine if the Vita remake got upgraded to 2GB of ram, a 1080p screen, and double shoulder buttons and a true dual analog experience with HDMI out? It would totally be worth the asking price, that should be $199/$229 right now, WITH a 16GB memory card.