You can take it as a repeat of this generation from Microsoft's perspective. If you want the definitive version of all of these games, XB720 is the console to buy, at least unless you own a high powered PC.
It likely means that they will then port (sort of as an afterthought) to PS4, which means an extension of your experience with the PS3.
Also he is likely referring to the 8 core rumor from before, which means PS4 might have a hard time getting ports if CPU is intensively used... A lot of this is unclear but these consoles might not be much like each other. Especially if Microsoft is going with 8 cores at 1.6GHz and 16 threads, while PS4 is going with a quad core with 4 threads (AMD's designs limit them to 1 thread per core) But if they really do stick with A10, they could at least have possibly more powerful cores.
We will likely know a lot more soon, I've been starting to hear rumors of announcements coming, there is CES soon, and that could be a place where they announce their consoles, GDC is not too far beyond that, but for certain by E3 we should know a lot more than we did about Wii U last year at that time.
I won't be so sure of that. Sony shouldn't be going for a bizarre architecture like the PS2 & PS3 this time. For proper third party support they will need to follow the PS1 model.
Console parity could be achieved if they follow this route.