First comparison. Explorer with '70s T-Tops, bridge position, into Helix preset with delay, reverb & stereo clean AC30s.
Thoughts:
The Vox is nice. It's got a little grit, and a good flow from low to high. I actually did this one last, think I strummed slightly harder.
The Classic with the Red Fasel has a big volume boost: The circuit itself distorts, especially heel down. The advantage is, heel down has a better change of not disappearing in the mix through a combination of sheer volume and distortion generating some grit. I really like the throaty lower half, but subtle it ain't.
The Clyde is clean and has a big range. It's quite focussed and has a very smooth sweep, the best "mapped" frequency sweep compared to the physical position of the pedal. The pedal actually has a few more degrees of movement, so it's got warmer heel and sharper toe down and that actually is a downside for me - live, I like parking it toe down with the neck pickup for repeatability and the Clyde is too sharp/thin like that. I could adjust the pot rotation but then the heel down will be too mellow, and I use that too..,
The Standard; The bottom half of the frequency sweep seems to occur in the bottom 25% of the pedal movement, so it sounds faster. It's kinda clean too, but somehow not as locked in as a Clyde.