Just bought one, I got the "H" model (high impedance) as I go into the volume pedal before anything else. If you go through your amp and other pedals and then into the volume pedal then Boss generally advises that the "L" (low impedance) model is more suited to you.
Absolutely brilliant! Gave it a run out at practise last night:
- Absolutely rock solid construction, built like a friggin' tank.
- Excellent thick rubber grip.
- It's a big pedal too so there's plenty of space for your foot to sit comfortably.
- Incredibly smooth action.
- Completely passive, no power connection at all.
- External tuner jack if that's how you like to wire things.
- Adjustable torque screw on the baseplate so you can slacken/stiffen the mechanism to suit.
- Minimum volume knob so the heel-down position can be set to a low volume rather than no volume at all.
I experimented last night and it's so much easier than rolling off your guitars volume knob. This basically just has an internal pot so it does exactly the same job only with your foot, not your finger.
I highly recommend. :D