[citation][nom]mitch074[/nom]Considering that Mozilla keeps 4 release branches (Stable: 8, security and stability bugs only; 9: beta, major bugs; 10, alphas, stabilizing features; and 11, nightlies, development) going all the time, claiming that by using version 9 you're on the edge is stupid.[/citation]
Umm, not so much. IME...
8 (Stable) is very stable, it is very unlikely you will run into problems.
9 (Beta) is also very stable, still unlikely you will run into any problems at all, but you shouldn't be surprised if you do.
10 (Aurora, Alpha) Stable-ish, you will probably run into a few problems, can be used for everyday browsing, but expect to be interrupted by bugs a few times a day.
11 (Nightly) generally unstable, hit or miss how many bugs you'll run into.
I almost always use the beta as my main browser; so far I have not run into any problems at all. Aurora and nightly get too annoying to use as your main browser with how many bugs it still has, not that their intended to be your main browser anyway...