TC Helicon Harmony4 demo
It has it's uses. To me, most of them are synthetic-putting it pre-reverb for example, or using it similar to how most people use the MicroPitchShift on the Eventide series although a different beast to be sure. Also cool for stuff like the hook in Elbow's Any Day Now (
http://www.youtube.com/watch?v=kPhhu4YxiE4 ).
This is also great for a greenhorn vocalist or producer than might be fishing for a harmony they can't think of or have never heard before (during the writing/demo stage). I wouldn't expect it to replace a good group of session background singers, but it can work in demo situations.
DVr2 is stellar. The Tube tech CL-1b is useable, but disappointing if you are used to using the hardware unit with larger amounts of gain reduction. I'd def get those 1st.