Kizer doesn't enforce MAP, so if you look around you can find the Velox 2 for $159.95. It's hard to find a ZT for less than MAP, so you're pretty much stuck with paying $240 for the 0456 unless you buy used.
I don't own the ZT0456, but I do own the Velox 2 and I find it hard to believe the ZT is $80 better. I also have a hard time with a 3.25" blade weighing 6.5 ounces. I have a feeling it would be a bit of a pocket brick, as that's a lot of weight packed into a small area. I like the look of the 0456, but I really can't see myself ever WANTING to carry it.
The Velox 2 is a sweet little knife. It's got a unique flipping mechanism, so if you like big flippers with lots of torque, you might want to try to get your hands on a Velox to see if it works for you. I almost discounted the Velox 2 because I already had a Kizer Gemini and the knives look very similar. They're very different knives though and I think I prefer the Velox in hand over the Gemini.
If I had to choose between the two, I'd have to go with the Velox 2 vs. the 0456. If it was the 0450, 0450CF, 0562, 0801 or even an 0808 you were considering, I'd probably call it a toss up.