I sell Sound Labs, and have recently heard current-generation Millennium-1's (A-1 equivalents) and Ultimate-1's, with the same amplifier and source material, though in different rooms. There are differences. The Ultimates do seem to go a bit deeper in the bass, and but the main difference was in the soundstaging. The M-1's are quite decent in this department (especially in depth of image) but the ultra-rigid metal frame U-1's throw a very palpable no-room-boundaries kind of soundstage that I simply haven't heard before or since. So yes, there are real differences, which may or may not be worth the extra ten grand or so.
