I'm a happy Tribby owner here. I have an ASAT Special and ASAT Classic semi-hollow that I play into a standard 1995 Blues Junior. The higher output of the MFD pickups really drive the Blues Junior well, whereas standard output Fender pickups tend to require a bit of clean boost before hitting the amp.
I fully intended to buy a black USA ASAT Classic that I'd had my eye on, but I preferred the neck radius and finish on the Tributes I played. I ended up buying 2 Tribby's for the price of one US model. I've gigged the ASAT Special for 5 years without any problem, though the electronics were scratchy and needed replacing under warranty. The ASAT Classic has been perfect so far.
I also have a USA G&L S-500, and the quality of the hardware (tuners, electronics, jacks) etc. is definitely higher than the Tributes. I would not say that the fit and finish of the neck and body were inferior on my Tributes though. In particular the ASAT Special is made out of some very nice ash and maple. I was VERY picky about selecting both guitars though. Play a few and you're bound to find some good ones.
Just be aware that Tribute guitars have virtually no resale value compared with the US models, so if you're intending to upgrade at some point you would be better off looking for a good second hand US made G&L.
Whether you buy a USA or Tribute ASAT you're still going to get some nice sounds out of the MFD pickups into your Blues Junior.