in the past, their high end stuff was good
(edit: just looked at their new stuff for this year...the darlington output stages are some bad *** pieces, McIntosh used those for a while.....that's some quality stuff btw)
basically on that rating, it means that it will put out 1200watts on one channel no matter what the ohm load on the amp....
I would HIGHLY doubt that rating, but look at the fuse rating and it will give you a better idea
HIGH end rockford fosgate (or rockhard prostate as we call it.....lol)
Honnestly, the higher end series of just about any company out there will be good
THD - the lower the better, my arcs run at less than .001% ALL THE WAY ACROSS THE BOARD! They are rated atlike 85 x 4, they will put out something like 175watts per channel and they they won't go above .001% THD until about 160 watts per channel, that's how clean they are....in general <.05% is good
sig to noise >100 is good as well
look at the damping factor as well, a higher number means that it will react more quickly to the changes in the music, as well as the amplifiers ability to control the speaker (in lays terms) (the arcs have a 2000 damping factor, most amps are in the 200 range)
hope this helps!