I've been playing through Bayonetta again on a higher difficulty, and switching over to the MGR demo was a jarring experience to say the least. Raiden's mobility, at least in the demo, is horrible when you're used to how Bayonetta controls. I felt like he was sorely lacking in combos as well.
Other comments, less tainted by Bayonetta-bias: The demo froze my PS3 on a couple occasions. I don't like the L1+R-stick shit at all. Parry being on the same button as attack is off-putting at first, but I suppose I will get used to it.
Definitely going to be a rental for me, since I was only in it for Platinum Games to begin with. I'm not a fan of Metal Gear in the slightest.