I've done the comparison between the V3 and the O2. To keep it short, my thoughts are below:
1. The V3 is smaller. By enough that it matters. The O2 would be a fine size if it had a 1/4" jack (earlier Neco portable amps were in a case the same size as the O2, but included a 1/4" jack), but it doesn't.
2. The V3 has better bass (without the bass boost feature being turned on). It's not an enormous difference compared to the O2, but it is definitely there.
3. The V3 has the optional bass boost feature, and it is well done. This isn't a huge difference, but it's an option you have with the V3 that you don't have with the O2. I find the bass boost useful with some Grados, for example.
4. The V3 has a "cleaner" front panel. The PSU jack is on the back, there is no gain switch, etc. My biggest gripe with the O2 is that the front is extremely busy and annoying when you have all the cables attached. Even the V3 has room for improvement. I wish the input jack were on the back, for example.
5. The V3 (or at least mine) has a better volume pot, I think.
6. My V3 has the upgraded battery, which is amazing. I don't use my V3 "on the go", in the sense of while moving. But I do use it when at my desk at work, and at home when I'm not near one of my dedicated listening stations. So while I don't actually need it to have any battery at all (I am always within reach of an electric outlet), I love not having to worry about the battery or power cables or anything. The battery just lasts forever. I think I've charged it maybe 3 times over a span of several months. It. Just. Keeps. Going. And going. And going. And going.... I also love the auto-shut off feature when charging. This is a huge win for the V3 all around.
7. The V3 can be charged off USB, the O2 cannot. Another big win. USB outlets for charging are all over the place and universal. This is another big win for the V3 in my book.
8. The O2 is MUCH more convenient when it comes to changing gain settings. The whole setting the jumpers thing is old and annoying on the V3, if you ask me. It is high time that Neco make this more convenient (and DIP switches behind a plastic cover over a hole on the amp aren't convenient, either -- I'm talking about a switch or a button).
9. I believe the O2 is cheaper, although I can't remember offhand. With the options, I think the V3 is more expensive by a fair amount. But in my view it is totally worth it.
Best regards,
Adam
