Guys thanks for being patient with me. I received the Vitus about 3 weeks ago but haven't bee able to listen to it enough until this week. There are already quite a bit of published reviews and forum threads that discussed the sound quality and characteristics of the RI-100. My impression is consistent with what the professional reviewers and forum threads said. First of all, this amp produces very well-balanced frequencies over all spectrum. Tube-like silk smooth high when I listened to the violins. Natural and life-like female Jazz vocals. The bass is deep and tight and that makes RI-100 stands out among its competitors. The amp paints a wide and deep sound stage and the instrument separation is excellent. Most importantly, it doesn't cause fatigue after long listening sessions. Like I said, this is the first week which I have a chance to spend enough time listening to the amp. Will do more listening in the next few weeks and keep you posted. In general, I'm very happy with this amp.