Dawn, I've had both, and both are fine fish. It really comes down to your personal preference as both these species behave pretty much the same. Personally, I like the Chevron better (but realize that as it grows other, it will change colors and lose the orange stripes).
No problems with the Kole in any form. I had it for several years then sold it due to a tank down grade. The person I sold it to still has it now, about 2 years later.
I love my Kole. They are said to be rather shy, but mine has alot of personality and keeps the tank very clean. I also was thinking about getting a chevron, but the color change made me think about the cheaper alternative, and just settle for the Kole.