Hey there...I've had the luxury of owning pretty much every wah out there, including the two you've mentioned. If you've got the bucks and are crazy about wah and have rackgear, i'm definitely recommend the rackmount crybaby. its amazing and what I use now with my setup.
Now, moving on to the switchless options; the Morley is a nice pedal. The own the basic one, not the bad horsie. Its old, but the optical
sensor works like a charm! Never any problems with scratchy pots which you're bound to get with other pedals (especially if you have a pet!!!)
The only other switchless one I can think of is the Weeping Demon by Ibanez, which is pretty nuts! As the name suggests, probably not for you considering you're looking for clean tones.
- Morley = very clear and defined. Not the biggest range in the wah sound...more of a vintage styled range on the one I have, though I imagine the Vai version has a bigger range (modern wah pedals have a larger frequency sweep for that huge Zakk Wyle type wah)
- Dunlop = Classic wah, great for psychedlic rock and the likes and really what you're going to want for cleaner sounds. It tends to color your tone a little more, but in general, this is a good thing!
- Weeping Demon = umm....the name says it all. stike
Another important consideration to make is the type of "wahing" you'll be doing. If you're doing funk style strumming with your foot moving the wah up and down with every strum....well, this can be hard if the pedal is stiff. The Morley pedal isn't the most natural or easiest thing in the world to make quick movements, though the stiffness makes it easier to make slowww sweeps with your foot and really feel out those wailing notes. The Dunlop is loosey goosy which is great for quick movements, but harder to really feel out those slowww wah lines, especially if you're standing.
Hope all this helps! Happy Wahing.