I went from the dk1 to dk2, and now cv1. The positive I can say is the cv1 has a bit better screen, but you can still easily see the pixels when the screen is bright. From the comments here and other places I thought they would do a better job at blurring and hiding them, but it wasn't very much different. The other good thing is 360 degree tracking. It felt like it has a bit better range than the dk2 and the FOV of the new camera is a lot better, Its very nice to be able to turn all around and still have tracking. Black smear is gone, but there is some red tint in some games. The headphones is a big plus.The comfort is ok, its lighter but the foam thing, that rests on your face is a lot harder and thinner than dk2. I couldn't find a really good way, even though i turned the angle of the hmd and tried everything with the straps, it still didn't feel that much more comfortable than my old dk2 but a little. Its a lot easier to take on and off so thats really nice.
The most negative thing is the lenses.
They are horrible compared to dk2. Everywhere there is a bit of contrast I see god rays all around. I am lucky and have a IPD at 64 so both dk1 and dk2 fit me perfect, the lenses there didn't blur more than maybe 10% out on the edge of the lenses. cv1 is just a blurry laser show all a round edges. so for me the visuals of the lenses is a downgrade. I tried to push the dk2 around so my vision wasn't in the perfect centre, and it got blurry fast on the edges, so I can see why people didn't like the old lenses if they didn't have a IPD in the average zone, but for me its just a lot worse. But I can't see why they couldn't keep the old lenses cause they implemented the lens adjustment so that wouldn't matter for most people anymore.
The FOV is a bit wider and a bit smaller on the vertical scale, but the thing I didn't like is that I can see the plastic insides and its a bit annoying, you always feel like there is something in your vision, that never was an issue with dk1/dk2 for me.
My recommendation if you have a dk2 and you are happy with it, you can wait to see if you get it cheaper as a package deal with touch, cause I don't really think cv1 is that much of an upgrade, at least without touch. its a new product and it has plenty of faults but Its a lot better than playing on a monitor:)