Hey,
First of all this is a very good wah pedal. Dunlop is very famos in making wah-wah's. And the new 535Q, i think is very usable and anyone could find a use to it in their pedal boards.
As earlier said, it has many tone variations, volume control and mode control, boost, which i personaly don't use, becausi it makes a distorted sond n my combo, which I dont expect from Wah. But some may find it useful.
I like a specific sound of wah on my combo, and many combinations of tone control gives the opportunity, which is a great + for this pedal.
Sometimes I like to use it as sort of volume pedal, turning the tone to narrow and vide, as it just disapears slowly.
On the negative side, I find that turning it on and of could be better, as it is for some other wah's, when you dont have to push it all the way forward, and when you do so, then it starts with shar sound, which I dont like sometimes.
But due to its features this wah has grown on me, and I like it very much.