I just got a Poison Black Belt. I paid $75 for it.
It jumps easy and the only other one that I have tried and liked was the Lucasi Air Hog. The Hog is much more expensive and they both jump effortlessly.
The difference in price between the 2 can't justified as far as I am concerned.
30 bucks is a decent price but with the Poison, double the price but also double the jumping power.
If you like to jump balls, it doesn't make sense to buy a jumper that is hard to learn how to handle. You will probably be giving up a ball in hand at least 50% of the time when you or the cue malfunctions on you. You are buying a cue to jump balls, not give away a ball in hand.
If you cheap out on a jumper, you will most likely regret pulling it out of the case most times and learn to use the rails instead.