Sounds great to my ears. I think that it's inevitable with a tone circuit that their will be some tone loss. I leave my guitar tone controls at 10 and let this do their job since that's essentially what they are. I'd say that it's not that much different from the tone knobs on a guitar.
It's natural to compare this to a wah, but it's quite different. This is much more subtle - transparent, but present. There's no chucka-wah funk here. Yet, you can get unique effects by combining tone and volume changes. It can approximate a wah, but much more organically. Very smooth.
For an example of the sound, check Dave Berry's "The Crying Game."
Reliability/Durability:
I've not had it but a month and I'd be reluctant to gig with it both because of it's rarity/value and because of breakage tales read on usenet.
Ease of Use:
For volume, you simply go up and down. For tone, you keep your heel planted and swivel the toe-end of the pedal left or right a few degrees. It's hard to imagine it being easier to control both at once. The pedal is much more comfortably sized than, say, the volume wah, but the mechanism takes a bit of practice. I'll probably be working at it for some time to come if I want really dynamic effects. For static control of tone with dynamic volume swells, it's fab. The gears are a bit noticeable underfoot - less glide-ey than newer pedals - and the pedal hits the medal on forceful volume ups, but these are minor flaws that are unavoidable.
No batteries or plug, which is nice.
Customer Support:
DeArmond is no longer around - although Fender bought them, Fender's got nothing to do with the pedals at this point. However, it's just pots inside and I think an inventive tech could repair it.
Overall Rating:
I'm pretty psyched about this pedal. It's nice to have basic tonal / volume control in one place without interfering with picking. I'm ecstatic to have nabbed it on Ebay ("BIN"), practically new, for $45 + shipping! In the subsequent weeks, I saw them as high as $172.50 for units in worse shape.
I hear that Fender made similar units way back when, so there's an alternative. If you see one, grab it. You won't regret it.
