I have a KTC-1 and it's a really nice uke. Strumsilly makes a very valid point that only 12 frets will limit you if you're an up the neck player. But, I really love the tone and the playability of this uke. I think a lot of it is just how light and gossamer the thing is, but i'm able to do difficult chord transitions much easier with my KTC-1 than my two other ukes.
Good luck finding one! I got mine new on ebay from Lucy's ukes on ebay, and it was an incredibly easy process. So, keep that option in mind if you don't find a used one you like.
I found my KTC 3 , and two other Kiwayas, to be tight sounding compared to Martins. I'd always put Kiwaya money toward a vintage Martin now.
Just my nickel opinion, f. Hope your luck is better than mine with the otherwise gorgeous (but limited resale value, I lost coin on all three, but never did on a Martin) Japanese brand K Martin knock offs. I figure if I'm buying a Martin knock off, unless it's 30 percent the price of a Martin, why not get the Martin. Kiwayas are, to my calculations, about 70 to 80 percent the price of a Martin. Too close.