I like it because it's an added value proposition- you don't have to spend a fortune on extra high powered amps just for the woofers because they are included. And the low end from them sounds fantastic! Apparently Legacy did a custom job on one of their bigger speakers, allowing the internal amps to be bypassed by the user if they ever purchase a second amplifier.
"It may be just me, but I'd prefer the woofers were passive (wired independently as subs), over a built in subwoofer amp in my mains. Am I alone in that?"
Gotta correct you on this one, as I recently visited the factory. They were not just voiced by ear, there was plenty of the usual test equipment there in use. Yes they are also signed off on by the designer, but it was not some shoot from the hip process. As far as using ones ear, I do think that is important too.
If you have a look at who uses Legacy, I think you'll see that they are quite popular among the people actually creating the music- Rick Rubin, L.A. Reid, Herb Powers, etc., Like everything in life, you either like them or you don't, but in a business where you can have any speaker you want, this speaks a lot to the quality of sound reproduction.
Also I have heard older Legacy speakers- they are still very good, however the new Legacy speakers are PHENOMENAL.
"The designer "Legacy's designer also likes to "voice" his speakers by ear, and you either like his choices or you don't."