Sushi,
it is hard to believe that any manufacturer would purposely under-spec their amp, but I guess in a way that's what companies like NAD, Rotel, etc. do. Their equipment consistently overperforms their own rated specs. Some people have said that they lower their 8ohm rating because too many consumers have caught on to the 'double-down' spec on amps and it has become an important buying factor. In that way it's kind of like THD where manufacturers figured everyone was paying attention to those #s and started to fudge them as well. Again, I'm not sure whether I believe that companies would underate their amps @8ohms, but anything is possible.
As far as actual output, I read the review from Sound&Vision and they tested output on the Sherbourn at 253Watts 8ohm and 381Watts 4ohm before clipping (this was one channel driven). And as you stated, output wouldn't be a whole lot different with all channels driven due to the monoblock design. So it definitely doesn't double-down, but does perform better than Sherbourn states.
So after all that, I'm still kind of torn. Despite all this rambling, I am new at this, so if anyone sees anything I've said to be wrong, please correct me. And please feel free to help out with any info or listening they've done with either of these amps.
Keep 'er coming, thanks in advance
Scott
