Older JBL AMPS

I have been watching these threads and have seen alot of good things about JBL Amps, i have a friend who has 1 and has set the record for 1 10" sub using a JBL AMPS, but these are the new style, My question is what about the older amps? are they just as good or not? Specificly the GTS180.

ANy help would be great!

Thanks

Chuck:flash: