ZT is a KAI brand (read: Kershaw) that has been around for a few years. They make a tremendous product at one heck of a pice point. Most of the early designs (0400, 0200, 0300, 0100....) were Ken Onion or Ken Onion/Strider designs for the fixed and folders. There are also a Galyean designed dagger and automatic, and a Hawk designed auto. A large portion of the newer stuff is done from in-house designs. The materials, ergonomics and warranty are all first rate.
Although I have never been a huge fan of the 0400 blade shape or the grip insert into the handle, the 0400 is a fine knife and very similar to the Kershaw Blur in mechanical execution. You can often find the 0400 at a very fair price b/c it didn't seem particularly popular (polarizing design), but, it is a fine knife that will serve you well. I would recommend the 0200 for, in my opinion, the all around ZT experience (price, materials, performance), but, different strokes for different folks.
Keep an eye out for some of the newer designs. There are several that have recently dropped or will in the very near future, and, there is a little something for everyone in that mix from both price and style standpoints.