As far as I can tell, the only difference between the UEW20SG and the Ibanez UEW10QM is the wood (this is spalted mango), the gold tuners and an extra $20 on the price. Because both ukuleles are laminated (cheap plywood underneath the top wood) the wood isn't going to make any appreciable difference to the sound. So it's purely a case of aesthetics.
Size: Concert (with cutaway)
Construction: Spalted mango (laminated)
Tuners: Open, geared, gold.
Finish: Natural high gloss.
Find it on Musician's Friend Price: $169.99