The Batman Arkham Asylum convinced me to buy the game so I wouldn't say every demo is meh these days. I played the demo on my PSN not too long ago. The game comes off as a bit ostentatious for me. It does feel a lot like a Kill Bill game to say the least or something that Quentin Taratino made.
Let's start with the graphics. I don't mind the grain filter too much, but the character models and environment leave much to be desired. Animation comes off as quite choppy, especially noticeable when you use your three hit sword combo. Music is a hit or miss depending on your tastes (miss for me it works for what the game's atmosphere).
The actual gameplay is where the majority of my beef is at. There is too much reliance on slow motion to succeed in the game. In games like Max Payne you have bullet time, but you don't necessary need to use it for every single gun fight. If you don't use any of Rubi's moves such as her slide, swan dive, or wall run to initiate slow motion - you'll be forced to use only one pistol, which fires painfully slow. For some reason Rubi will only use her dual pistols when she enters slow motion. This makes the game feel a bit repetitive because there aren't too many options for combat compared to games like Devil May Cry or Ninja Gaiden.
If you want to play as a badass female protagonist in an action game, I would personally wait for Bayonetta (360 and PS3) early next year. That game is definitely more polished from the looks of it and it is created by the creator of Devil May Cry.