My svt seems to only go out for bigger outdoor shows these days, but man when it does, it sounds great. I have a gk system that I use mostly for club gigs, because it is so portable. On the down side, the gk system, with its focus on being lightweight, gives up some reliability. I have blown a 12" speaker on a neo cab, and now the mb800 is not working. Neither were abused, just gigged a lot.
The Ampeg on the other hand, is a solid workhorse and shows no signs of slowing down. The 810 cab is from the 70's, and I bought it used from Throughgood music in Tampa in the early 90's. It sounds as good as the day I got it.
I like both systems but the Ampeg, in my opinion, is built with longevity in mind. I guess it just depends how much the sound it worth hauling it.