THE best ukulele player in the world? The best, in which regard? The best picker? The best strummer? The best chord melody player? The best to accompany himself while singing?
I don't know. And honestly, I don't care. I do know for sure, it's not me, though...
I might be in a poll for the okayest, ok, one of the okayest ukulele players of the world... ok, of my continent... well, my country... hmmm, my town? Maybe my part of town... well, my block, for sure!
I do like Aaron Keim's work a lot, although I am aware that there are a number of players with a better technique and a higher level of virtuosity. James Hill, already mentioned, was pretty impressive. Not only as a ukulele player, but as a musician. Much more than all those fretboard acrobats, who draw a lot of attention, and I realize why. But I can't help myself from being bored my most of them after a short time.
I think there are so many different styles not only of music to play on the uke, but also of actually playing the uke: some play finger style on their low g tenors, others play a much more percussive style on their vintage Martin soprano. Some days I prefer one thing, on other days the other. I keep enjoying the many different possibilities the different types of ukes offer, without wasting too much time thinking about who may be the best. Rather spend my time playing one of my ukes.
But I'll keep on reading any upcoming answers here. There might be inspiring stuff coming up.
Just my 2 cents... no offense intended!