I've tried most of them, the 15, 40 and 120. Most people seem to like the 15 the most. Strangely I liked it the least of the group. I don't know that I would call it Voxy, but it had a pretty good vibe, little more Fendery to my ear. Personally I thought the 40 was a really versatile amp, little less gain, but had a lot going on for it. The 120 (can't remember the model but the metal sound one) actually sounded really great for metal stuff. I don't know how well it handles other sounds, but it certainly does that well.
That said in the 15 watt small amp world there are a lot of choices out there now, and this one is just as good as most of them out there. So it might fit the bill really well for you.
I am looking for a lightweight amp to tote to jams. The DVM Galileo at 28 pounds seems to be about half the weight of other 15W amps.
When you say that most people seem to like the 15 the most, is there a forum where this has been discussed? I can't seem to find much in the way of user reviews.
I've tried them all and like the 40w 212 the best. VERY chime-y tone. Not tons of ultra clean headroom and I liked it much better with single coils, but then I'm a sc guy. I really like its juicy, chime-y tone. Not a creamy lead tone, but killer stingy blues or Edge-type tone and 40 lbs is easy tote.
The 666 head is killer metal tone, but not really my thing.