OK, I got my Mini and tried it out yesterday and today. I have a 315, 325, and 415 on the way. In for a penny, in for a pound.

I wanted to take them all for a spin and I can use the remnants elsewhere, sell them off, or whatever. My current thinking is that the 415 is going to be my main HT unit. It's the most 'soundbar' like unit and the unit with the most power.
Anyway, the Mini both pleases and disappoints. The disappointment is in the max volume. It's loud, but not loud enough for even a medium room. More suited for an office or bedroom or personal area. You need to be sitting fairly close and directly in front of it for the best sound, though off axis the sound is still good, you lose a lot of the "phasecue" effects. (I'll be doing a full review later, this is just a "first impressions" bit.)
The good news is that it's a quality built unit. Heavy, sturdy, plenty of nicely done screws holding everything together. Very solid and classy looking in the white finish I received. At the price asked, I would expect no less ($199). It has a heavy power brick. Uses 3.5 mm jacks for the audio in and has a dual in/out use 2nd jack that (fortunately as it turns out) can be used to hookup an external sub-woofer. And one will be needed. Though it has fairly nice lows, it definitely does not have anything close to the bass response of a good sub-woofer.
The sound is very clear and accurate, my guess is that it's fairly flat between 500 and 10K Hz. Vocals are very clear and distinct, percussive sounds very nice (snares, blocks, things like that sound great!), guitars, saxes everything in that range sound super. I have not yet listened to enough variety of material, but so far, so good. Music sounds good (with just a touch of phasecue).
The problem is lack of power. It sounds like a great small box, but definitely a small box (without the sub-woofer). In fact, so far, my impression is that it sounds best at about 70% of the full volume range. I think it's straining at full volume (which, again, won't be full volume enough for many).
I've only played one DVD so far (the ultimate ed. Terminator 2, one of my standard test DVD's) and I actually felt it did a very good job. Again, sounds are very clear and distinct, crisp percussive sounds, nice throaty Harley, very clear dialog. The phasecue definitely does extend the perceived soundstage. It's not even close to surround sound, but it's a pleasant effect and does have a 3-dimensional feel, with things seeming far away or close, off to the left or right, and so on (but not behind).
Again, there's just not enough Ummph! (power) in my opinion. I'll be hooking up a sub later to see how much that helps. But for now, this sounded good, but only for a small setup, definitely not for a main room, or even a medium room. At 5 or 6 feet it's OK. I'll have to experiment more as my placement of the unit was far from ideal during this early listening experience (out on a table in the middle of a room w/a portable DVD player - hey, I was working quickly!). Placing it near a wall would probably help the bass response quite a bit (the port is in the real of the unit).
So, quick summary, feels a bit light on power, excellent overall sound quality as far as clear, accurate sounding delivery - especially of the DVD movie. With music, it did very well, but the phasecue was less effective and it sounded best to me with the phasecue at minimal settings, just enough to open up the sound a bit.
When I hooked up my mp3 player, it worked great, but when I turned it up the short-comings of some of the mp3's were clearly evident given this units crisp, full range reproduction. With quality CD's it sounded great. With my Roku Soundbridge M1001 internet radio it sounded super (in fact, this was one of my favorite pairings).
So I would class the Zvox Mini as something like the Apple ipod deck, the Bose Soundwave system, and other similar sized systems. I'm guessing it might make a pretty good gaming sound system, too. It's about the right size, strong enough to support a monitor on top, and the phasecue would probably work fairly well. As a bedroom sound system, I think it would do well. Or a personal small office system.
It hints at what might be possible. I'm hoping the larger Zvox units will live up to that promise and deliver something more suited for HT use. We'll see.
Oh, the vocals and dialog were indeed very clear, distinct and easy to understand, noticeably so, in fact. So that trait seems to be true as reported. The strong mid-range and accurate reproduction probably account for that. And the system is a breeze to setup with its simple design.
It is indeed a "mini" type system with hi-fidelity and a nice clear sound. Suitable for small spaces. I will be keeping it and using it for personal office DVD viewing on small screens, for internet radio and CD/MP3 music and that kind of thing. It's a fun unit to fool around with, fairly portable, and worth the price paid, I think.
2009-01-28 Update: After some more listening and some tweaking of the sub-woofer output setting, I got much better bottom-end with the music and this also helped the overall sound level and power perception. It *is* a mini system and definitely for a small to mid-size room, and the max volume is limited, but plenty loud for normal use. Overall, I am much happier with the sound now than earlier. You have to sort of tweak the phasecue, sub-woofer and unit volume levels to get the best results, the final results are very nice, definitely a high-quality sound. So +1 to the bass output and +1 to the overall sound quality.
The bass will distort if you turn the sub-woofer to max and the volume to max, but that's not really surprising. For music, I currently have the sub at 50% and the volume two clicks down from max. I then control overall volume via the source device (in this case, my Soundbridge). This is the way the Zvox's are all designed to work, although the later units offer more control on the remote. I dound that thanks to the clarity and presence, I can listen very comfortably at lower volume levels. In other words, you do not need to turn it up way loud to get good fidelity, as we were all wont to do in our youth.

The quality with good source material is very pleasant and you will definitely hear the flaws in poor source material. You can tweak the PhaseCue depending on the music content (i.e. classical vs rock) a bit, but you could just set it and leave it, too. You want just enough PhaseCue to open the soundstage for music, in my opinion, though with some material you can go hog wild. So usually, I have PhaseCue at about 1/3 of max for music and 1/2 to 2/3 for DVD's. But I'm still experimenting, listening, and learning.