I've been using a Roland EV5 expression pedal for the past few years. It's worked fine with my Roland boards, and when I switched to Kurzweil, it worked ok with them too.
Recently, the wire on my pedal (which is hard-wired to the pedal) started to fray, and instead of rewiring the pedal, I decided to look at other options. After reading that one of the techs who sets up Kurzweil setups for Broadway specs the Boss FV-500L pedal for all his setups, and has never had one fail, I decided to check it out. I haven't spent too much time with it yet, but so far, I love it!
This pedal is a huge improvement over the Roland. Here's what I like about it.
1) The throw is great, with a wider sweep than the Roland.
2) The resistance is adjustable.
3) The feel is great.
4) Solid build. Its metal instead of plastic.
5) Can be used as an audio volume pedal as well as an expression pedal.
6) The larger size and rubber grip means my foot doesn't slip off.
7) It's heavier, so the pedal doesn't slide around. It stays in one place.
8) It uses a separate cable, instead of a built-in wire, so you can easily swap out cables if one starts to go. (The Roland cable is permanently wired to the pedal, so if there's an issue, you can't just swap it out.)
The feature set includes stereo in/outs, an expression pedal out, a tuner out (to send your guitar signal to an external tuner), and a min/max adjustable volume pot.
The only issue I notice with it, is that when the pedal reaches the end of the throw, the sound of the pedal hitting the rubber stop is louder than I wish it would be. This is not an issue for live playing at stage volumes, so much as for practicing at moderate volume, where it can be distracting. It seems like it should be possible to put a very thin pad in to solve this problem without impeding the full range of the pedal. (I tested this quickly with a folded paper towel, and the noise was almost entirely gone.) I'll see what kind of more permanent fix I can devise.
If you're looking for an expression pedal for your keyboard, (or a volume pedal for your guitar) you might want to give this one a look.
Amazon has it here: