I would take the MTX over Fosgate. First Fosgate amps are more money for less real watts than MTX amps. Next Fosgate amps run hotter than MTX amps. The Fosgate amps might be built a little better and they look a lot better than the new MTX amps.
Everyone says that, but I haven't seen any proof to back that up. On RF's website, it shows the spec's of the old mottle, then the specs of the new mottle. There isn't much of a difference, if any, the new ones have been improved.