in term of sturdy one, i like m audio one
in term of cheap and working one, i like proel one
Moog one, is too big for the size and if wanna use for moog pedal(the value of the pot inside work best with moog pedals) If not, there are cheaper alternative
peep is using a light dependent resistor(LDR) if not wrong. While its a cool thing to play around with, if really want to control effect parameter and use it in normal way. Go with the traditional expression. Playing with LDR unless you can control the surrounding light and make sure the condition is sorta fixed when you wanna control the parameter, if not, can be either really cool, or really way off when controlling the parameter
theres nothing much inside an expression pedal other then a pot, stereo cable and plug.
as long as the exp pedal work with the pedal and the entire sweeping range of the parameter being controlled work withing the entire range of the exp pedal sweep, it ok.
Heh, if really wanna be playing with expression pedal, get a cheap one, buy cheap linear pots from simlim, interchanged with different value to get the best sweep, for which ever parameter we want it to control. Throw in a dpdt switch, you can change the orientation of the exp pedal sweep as well. Its a simple mod for exp pedal and its one of the mod for toneczar modded eb expression pedal as well.
in short, a cheap exp pedal and expensive exp pedal, theres not much different other than the value of the pot inside and the material for the casing. Go with the one that fit budget and work with the pedal.