I had a Guardian until about 2 months ago when I traded it for a General. I really liked my Guardian, but the General is a little smoother, more forgiving with a long brace height, and IMO a better bow. Like has already been said, the cams are better, plus you get the roller cable guard instead of the slide and the shortstop. The only thing is that on the General you have to use a bow press for everything and on the Guardian you don't.
I liked both bows and I am sure you would too. As far as one being faster than the other, I have never shot either one through a chrono, but have shot both on a techno system that gives arrow speed. My Guardian averaged around 309 and my General is always around 317. I expected it to be slower, maybe its because of less weight on the bow string (no kisser button or string silencers).