Let me start off by saying that I absolutely love resonator instruments, and have been a fan of them for most of my life.
I have one of the Kalas and enjoy playing it a great deal It initially had the same issue with strings breaking at the tailpiece, but after removing and deburring/polishing it a bit it's been just fine. The only complaints I have about it are that the A string seems to have slightly lower volume than the rest, and the fret job was absolutely horrific. It's as though the frets had been leveled (quite nicely, I may add) but they skipped the corwning and polishing stages. It's not a huge deal, and I'll tend to it one of these days when I take the strings off to change them.
Sound-wise, it's pretty nice. It's louder than my regular Kala tenor, and has some of that resonator sound but the overall tone almost seems like a mix between a resonator guitar and a banjo, which is what I've found with most resonator ukes. It lacks the ringing sustain that both my Dobro guitar and Dobro bass possess. One really cool feature (depending on whether you like it or not) that is has is a nice "reverb-y" sound to it. It's hard to describe, but almost as if it's playing through a plate reverb - which, I guess, it kind of is given the shallowness and small diameter of the resonator.
Other than the fret job and the rough spot on the tailpiece, the finish is pretty good, maybe a bit better than onther ukes I've seen in it's price range. It has a well-done tobacco sunburst, and the back of the neck has a sunburst/fake fade to the finish. It comes with an open grain satin finish, but after playing it (a lot) daily for about a year the back of the neck is as smooth as glass and nearly worn down to the bare wood in spots. The lower bout around the f-hole has taken on a distinct sheen as well (from my crappy and sometimes overenthusiastic strumming technique).
One thing I really, really like about the Kala is that the piece that goes over the strings covering the resonator is removable with four screws. Doesn't sound like much, but it means that if you ever have to access the bridge or biscuit, you can do so without having to pull the entire resonator cover. This is something you'll really appreciate if you've had to do setup work on other resonator instruments.
A good friend of mine has one of the Recording King metal-bodied concert resonators, and I've spent a good amount of time playing it. It's beautiful, well built instrument. I find it's tone to be even thinner than the Kala's, but it does have a bit more sustain. I actually auditioned several of these as well as several of the Kalas before purchasing mine. I prefer the tenor scale, so that was the major reason for selecting it over one of the Recording Kings.
I highly recommend that you try before you buy. The sound varied quite a bit between the ones I've played. As was mentioned prevously, the fit between the cone, biscuit and body is pretty important.
All that being said, I'll more than likely acquire either a Dobro or National resonator uke in the future, just because I'm a huge fan of the brands.