I've got the Magnaflow cat-back and like it...
"Gentleman's rumble" is how I'd describe the sound - not overly aggressive, but definitely noticeable. No drone at cruise, and the straight-through design doesn't compromise flow at all. Compared to the Flowmaster 50 setup I had previously (2.25" DI/DO), the cat-back system seems less restrictive. Some of the difference could be due to the larger, mandrel bent pipes that are in the cat-back compared to the muffler shop pipe bends, but the mufflers are certainly different in design (FM = chambered, MF = straight-through).
As far as external appearances, the polished tip and muffler show no signs of rust. However, the exhaust pipes themselves are no longer shiny - there are varying types/qualities of SS... the pipes are the magnetic version and therefore are not "true" SS - and have discolored over the past 8 years (installed July 2006). Even with that, they are still in good shape.
Hope that helps