I've heard a few people speak highly of the G7th capo, but at $30+ it was a bit too rich for me. And I was very happy with the Kyser caypos that I have (two; because I'm always losing them)
But then, on a whim, I bought myself a G7th and have been using it for a few days and I have to say that I really like it. There's no spring to fight, you just slide it over and push it together and it locks on (what it really does is not release until you push the lever on the back.)
Works very nicely and easily. Expensive, but put it on your list of cool gadgets to get when you have the money.
Makes a nice gift too ;)