How does a super mini meta(v2) compare to a normal-size(penguin/altoids, 1x9V) JMT/tangent-built CHA47? I've been thinking about getting the CHA used(several of them online) for my new 770's(and later, for when I get my alessandro MS1), but having a really portable amp that sounds as good as an average meta is appealing, esp when it goes back down in price to within $30 of the CHA.
V1 of the SuperMini did not provide the same sort of impact as the CHA47... did not have the same fullness of sound spectrum as the CHA. Was very portable, very clear and detailed.... but almost a bit sterile sounding, especially before the SuperMini was burned in. After burn-in, the sound improved, but was still a notch below the CHA47 per my ears and equipment.
V2 of the SuperMini is a much fuller sounding amp that outshines the CHA in every way... better bass, better midrange, better highs, more air. It's hard to quantify these differences, but during A/B comparisons, there are discernable differences to my ears in my rigs.
Don't get me wrong, I truly enjoy the CHA47! It's a terrific amp that fits an important (at least to me) need... it's able to improve the sound of my portable rig without big increases in weight or cost.
So, which one to go for depends on what the priority is for you.
If cost is the main concern, used CHA47s are VERY reasonably priced. Heck, NEW CHA47s are very reasonably priced!
If size/portability is your main concern, then the SuperMini should work well.
If battery life is important, the SuperMini is a very good deal. With the CHA47, I was going through a new 9V per week. Yes, I should have gotten rechargables... that's another issue. But the SuperMini has extraordinary battery life.
Unfortunately, it appears that Fixup isn't taking orders for the SuperMini right now. If immediacy is critical, you can always go with other DIY folks at this site (JMT, Eric343, Tangent, KurtW, others?) to make you a META42 that's slightly larger, but that other folks at this site have reviewed and have said is better than the V1 SuperMini. Unfortunately, I'm not aware of a review of the V2 SuperMini compared to a traditional META42. If someone wants to provide me with a more traditional META42, I'll be happy to provide a review!
The bottom line: these are both good amp designs. You will likely notice an improvement in the sound over your current rig no matter which amp you go with.