Wirecutter's backup pick when the Kala KA-C is out of stock, and Reddit agrees Donner delivers solid build quality for the price. Concert size, mahogany body, plays nearly as well as the Kala for less.
Donner is the Kala KA-C's shadow — almost as good, slightly cheaper, and worth grabbing if the Kala is unavailable. Don't overthink it.
“If you can't find the Kala KA-C concert uke in stock, the mahogany Donner DUC-1 Concert Ukulele is another good choice. This affordable, concert-size uke plays well and sounds almost as good as our Kala KA-C top pick.”