Well, I had the opportunity to get a Marshall AS50D and, wow, is this an amazing amp. I had been looking at a Roland AC60 (very nice, as well), and a Fishman Loudbox Mini (also very nice), but I kept going back to the Marshall as it both keeps the more delicate part of the ukulele sound alive (does not color it) but also manages to give my ukulele a sort of body that belies the fact its lowest note is middle C. I am thinking it is the closed box design that all of these amps have that give them all a nice, tight bottom, but I'm not sure. I do know that the Marshall seems to have the most flexibility - its got very good chorus and reverb effects that are totally assignable to the two channels (one, both, or, in the case of the reverb, a balance between channel 1 and 2) and I love the fact that the tone is simple - bass and treble - all I need. Any of the three amps would be great choices for ukulele, but the Marshall just seemed to sound the most correct.