I don't think it's actually available yet. I know that Todd (the vinyl junkie) was supposed to get in a demo a long time ago and I've never heard a peep about that and I have yet to hear about a single purchase here on Head-Fi.
Well, I am the guy who posted the article quoted by palchiu. I can't figure out precisely how the sound is. In my oppinion, Eartube is quite like Prehead (or HA): fast, pretty wide sound stage, and airy. One thing different is slightly warmer than HA, prehead series, but not regularly warm or slow like the normal tube-amp that we know.
By the way, all you guys who have interests could search the old posts in Head-fi, and there are two or more that I totally agree with their comments. They are more precisely though.