I think the problem with the A6 is (beyond the weak presets) that everyone seems to want to compare it to some other synth. It is not a Mini or a Memory Moog. It is not an Oberheim (though it comes closer to sounding like a Matrix 12 or Xpander).
But, how many of the classic vintage synths do people talk about in comparison to what else they sound like. The Moog sound is pretty unique. So is a good Arp, but it is not a Moog. Oberheim and Roland have distinct sounds and capabilities. SCI products have unique sounds as well.
I think that in the right hands (which might exclude mine), the A6 is a very powerful sonic arsenal. Two seperate filters, Two VCOs with sub oscillators, sync, multiple waveforms and tremendous modulation capabilities. It is a monster in its on right.
My collection includes Voyager signature, LAMM Memorymoog, ARP 2600 with duophonic keyboard amd Moog Ladder filter, Prophet 10, 5 and VS, Roland SH 101, Super Jupiter MKS 80 + Programmer, JD800, JP 8080, Alesis A6, Waldorf Wave (the big one), Oberheim 4 voice and Xpander, Elka Synthex, Nord Modular, Novation Super Nova II and some EMU boxes.
I tend to think of each of them (except the EMU boxes) as being unique instruments. To me, only the Super Nova II and Roland JP 8080 are boxes that try to sound like something else. However, they really don’t sound like anything unique on their own.
One other thing, when you look at digital modelling synths, turn off the effects (same for the A6) and listen to the sounds on their own. It is easy to add some chorus, reverb or echo and make a weak synth sound good. However, a strong synth rarely needs those things and when effects are combined properly, watch out.