Any suggestions on a distortion that sounds good on acoustic?
I find it helpful to use a gate and good EQ section to tame feedback. The Devi Ever Hyperion is the best gain pedal I've played by itself on acoustic. It has a great natural gate, very little high end feedback and if you voltage starve it you get much more low end and lower gain OD and crunch.
Another thing to really consider is the quality of your acoustic pickup/preamp setup and if you're using an acoustic guitar amp. An acoustic guitar with a good electronic setup that has the correct impedance can be connected to a regular guitar amp. That in turn opens up a ton of choices of effects that can be applied. I've never tried running regular guitar effects into an acoustic guitar amp, but I can imagine it might not work as well since acoustic amps are usually voiced differently.