Back around Thanksgiving, I tried out a viola I liked. I mean really liked, but both my present and former teachers warned me against falling in love with the first nice instrument I tried, so I sent it back.
The shop handling that viola graciously offered to send it to me again so I could compare it with the Stopka. It arrived a couple of days ago, and I've been playing both the instruments, trying to be as objective as possible. It's hard not to love having such nice instruments to play on, though, and the fact that I have begun calling both violas by nicknames does not speak well to my objectivity. Anyway, some observations:
The non-Stopka is 1/8" smaller than the Stopka, but very easy to play. This could be because it's strung with Dominants, which I dislike, but which are pretty low-tension (should I buy this one, those strings are coming off immediately). Or it could just be that the size and shape suit me. The neck is small and easy to get around. To my great surprise, I am just fine with the low, side-mount chinrest it came with. I have a long neck and sloping shoulders, and usually need a super-high chinrest (like the Kreddle, or SAS), but not with this instrument, for some reason.
The non-Stopka has a nice tone, though somewhat thin compared with the Stopka. Again, this could be the strings. The A string (Larsen) starts to sound especially weak above 4th position. The dynamic capabilities are such that even I can get nice piano and forte out of it.
I recorded myself playing a 3-octave C major scale, slow and legato, on all 3 instruments (Stopka, non-Stopka, and my viola). The only recording device I have is my phone, which sucks, but I tried to minimize variables so all three recordings would suck in the same way. I was very surprised: even on that crappy recording, the Stopka got some of those tones I like so much. It sounded better than the non-Stopka and better than mine, but not tons better than mine (well, except for those wondrous tones. But my viola came closer than I thought it would). Which makes me wonder if it's worth the asking price, which is tons more than what mine cost. I also wonder if I will be able to coax nice dynamics out of it, like the non-Stopka.