It all comes down to personal preference and what you want to use it for.
Absolutely love my FLX Challenger for upshots and short holes - gets more use than any other disc in my bag (really) - but it's too OS for my putting style, so I putt with an APX.
That said, I've seen guys who are deadly in the circle with a Pro D Challenger... works for their putting style: banging chains with authority.
If I were forced to carry only a single putter, I'd have to go with something that wasn't quite as OS as a Challenger to enhance my performance in the circle, yet still have some overstability so I could use it for short tee shots and upshots... sounds a helluva lot like a Wizard to me.
More than any other type of dis, putters are about "feel" and what works for you, and less about technique and "the numbers." Obviously, Wizards work for a lot of people.
Given all that, I didn't vote. :|