I am using Keith McMillen's Softstep Foot Controller. It's totally cool: absolutely tiny, light as a feather, yet ready for stage use & abuse (some say it's even beer-proof!) and the best: it gives you not just a jack for an exp pedal, but allows you to control up to 6 parameters per pad. The pads are small, but at least the x- and y-axis are easy to use to change values (parameters), which is enough for me (i.e. two parameters plus volume or wah with the pedal per preset - cool!). The target of each controller can be changed per patch (so i can increase/decrease compression and amount of chorus on my clean patch, gain and delay on my crunch patch etc.). The possibilities are endless.
The controller can even be set up for five preset change pads (lower row) and control changes on the other pads. You name it, you get it. Programming it gets really manageable with the editor app for the Mac/PC).
Plus the controller is powered via USB (with the optional USB-MIDI-Converter box, which stays in my rack). So the only cable I have running to the pedal is the usb cable.
Extremely cool solution.
One backdraw, to be honest: the cool backlighting doesn't work properly when you play guitar, because the guitar acts like an antenna and produces noise. But switching that off is easy and you still have the LEDs on the pads which can even have different colours (depending on what you use the pad for).
I am completely happy with it. I had the Behringer in former times, it was ok, but difficult to program and waaay to big and heavy. The Softstep is soooo small and cute...;-)