CM GX units should be avoided = not very good
The Silverstone is much better.
If nothing is wrong with your current unit why change it?
I'd buy a Corsair or an XFX over a Silverstone though if you absolutely think you need a single rail unit.
They say 1 12v rail is better than two. FSP has two rails.
what do you mean "something was fried"? Does your current PSU work or is it dead?
actually the FSP has one rail that has been split in two (as do most PSU who state multi-rails but are under 1000w) so the whole argument of single rail vs multi is moot at 500w. The real question should be "does your current PSU work?" if not "what is the best quality PSU you can get that will do the job?"