I just got home with my freshly purchased copy, and I ran through some of the scenes.
First of all, the menu is pretty fucking horrible. It's a still shot with the options. There are only eight chapters as well, which is pretty bad considering it's a two and a half hour movie.
Second, while some scenes (the well exploding) look okay, there are some scenes that are ridiculously grainy. Obviously Paramount wanted to hop on the Blu-ray train as quickly as possible and make money rather than showing some quality stuff.
Honestly, I would have looked for it on High Def Digest or something first, but, of course, none of the Paramount Blu-rays have reviews yet. I was going to pick up Cloverfield on Friday when I got my first paycheck from my new job, but if it is going to be as bad looking as There Will Be Blood, forget it.
I've been watching Lost on upscaled DVD with brandonh83 and it looks better in some places than There Will Be Blood.