Buhwah buhwah
I had an original crybaby (maybe from the 70s?) that finally died on me a few years ago and I've been trying to replace it ever since. So over the past few years I've collected about six or seven different wahs. They are all a little different, and it really depends on what you're looking for and how that particular wah works with the rest of your gear.
My friends came over (one with an Ibanez Weeping Demon and one with a Vox wah) a few months ago, and we had a chance to A/B them all. Included in the bunch were "the original", the "classic" the "Hendrix" wah and the "535Q".
The biggest winner of them all - the best sounding to all our ears - was cleary
the Fulltone Clyde Wah Standard. This pedal had the clearest tones, the best true bypass, and the most useable sound. Everyone agreed hands down. The pedal did, however, take a little getting used to b/c it has a huge range from lows to highs and is rather sensitive. It also has a weird "Q" in the mids somewhere, but still overall the best sounding - significantly over the rest of the bunch.
The next favorites of the bunch were the Hendrix,
the 535Q and Vox, in that order. All the rest were OK, but there was A LOT of tone sucking going on. A Daneletro "Dan-o-wah" (which was somewhat of a fun novelty and retro cool looks too) was the noisiest and thinnest sounding of the bunch.
We tried them all on a few different amps, paired with a few other drive pedals and such. There you have it. Your mileage may vary.