I have the Kala. It was my first ukulele. I'm a music teacher, and have played guitar for about 20 years, so my expectations are high-ish.
The Kala has a nice tone, but it's a bit muffled. It has a small soundhole, and I think the top is a bit on the thick side. If you want ukey boxiness, it's good (though decidedly different from mahogany boxiness). If you want clear ringing trebles, not so much. Intonation is good, but not perfect. It's certainly very good down at the bottom of the neck, but if you want to go over the 10th fret or so, it gets shakier. Not bad, just not perfect.
I replaced the bridge with Tusq, and really wedged it in. Kala bridges (it seems to be agreed) can be a bit loose. This reduces the energy transfer from string to top, which is where most of your volume comes from. So, the Tusq gave a bit more brightness, a bit more sustain, a bit more volume. Not huge amounts, but for me, it kept me happy for a couple months more.
It's a bit heavy as ukuleles go. Not heavy, but heavy for a ukulele.
My main complaint was an uneven fretboard edge, particularly on the A side. That resulted in me pulling the A string off the board every once in a while, which was really irritating, as there isn't much you can do, other than recut a nut, which I didn't want to do.
After a year of loyal service, I got a custom MP ukulele, and have hardly touched my Kala. All that said, I have very fond memories of that ukulele. It sounded as good as any of the ukuleles my students brought in, from other Kalas, to Lakas, to Lanikais, to Brunswicks to Makalas (amid a range of genuinely cheap ukes). The only one I think is close is a spalted maple, spruce topped Kala soprano. That has serious brightness. Nice tone.
If you have any other questions, just let me know. I got mine from MGM, btw.