1. False. The AMD v. Intel myth when it comes to Beryl is absolutely false, however, it is true that Beryl has less issues with ATI cards as opposed to nVidia cards.
2. Gaming and Linux do not match at the moment, for the most part. You can try to use Wine/Cedega (NO, these are NOT emulators), but if you can confidently classify yourself as a gamer, you probably don't want to keep Windows around in order to game.
3. Yes and no. Some things run slower than Windows - however, compared to XP, it can run much faster on older hardware, or if you have a custom kernel (NO, I do not recommend trying right off the bat.)
4. Yes.
5. Yes.
6. No - but you need to be very, very familiar with your hardware. And very, very patient.
7. Pros - free, potentially speedy, customizable, stable, and I could go on.
Cons - potentially steep learning curve for Windows users, lack of good gaming support.
One more thing - don't headrush into Beryl right away for three reasons. One, it's not very stable at the moment - there are a good deal of issues with it, and for me at least, it just serves as eye candy - nothing more, really. Two, you want to get a little experience under your belt with the more common parts of Linux before you go jumping right into setting up eye candy.
Three, and perhaps most importantly, Beryl will cease to exist here soon - it is to merge with Compiz, a similar project, which is likely to be a lot better.