Well, the U-Bass (Passenger) didn't cut the mustard, either. This one had some seriously badly stripped screws on the gears of the tuning machines, and one of them (the E string) just fell off when the string was loosened. It was horrible quality control, something I didn't expect from Kala. So that one just got shipped back for a refund. I'm so far 0-for-2 in ordering a bass ukulele from Reverb. It appears that the lower-end Kala U-basses aren't any better than the cheaper models elsewhere. In fact, they all kind of look very similar, which tells me that they might be made from the same low-cost factory in China. I probably need to go north of $300 for a decent-quality U-bass, but I'm going to hold off for now. Because...
Interestingly enough, I stopped by a Sam Ash on Labor Day, and came across this
ultra-low-cost model. And surprisingly, this was of much higher quality than the Hadean and the Kala that I just sent back. No fret buzz, no badly stripped tuning machines, just very easy to play. This one doesn't have a back access or dot markers on the side of the neck, but for less than $100, I could live with it. (My left hand actually fits through the soundhole, so I can change strings without huge difficulty.) Also, the intonation at the higher frets is a bit of an issue, but I understand that it's an inherent problem for bass ukuleles with rubber/plastic strings.
So I guess I'll keep this around, at least as a backup. And maybe in a few weeks I might get a higher-priced (and hopefully higher-quality) one, almost certainly locally. I got burned by two bad ones from Reverb already.