I think most solid wood ukes from reputable brands are going to sound pretty good. You can always adjust the setup, so in my opinion it just comes down to appearance. I think anything from Mainland and above should be just fine. From my recollection the best factory made concert uke I've played in terms of sound was a G-String concert, although that particular one sounded better than other examples of G-String concerts (also good) I've tried. All KoAloha concerts I've tried sounded very nice as well. Basically I think if you choose your favorite design and buy from a reputable seller, you'll be happy.