As has already been said : excellent service but don't expect sales on the cheap traffic (use it for trades).
How good it is depends on what you use it for and what kind of traffic you choose. Choker has paysite, freesite, and blog traffic in beta right now. Not enough to purchase really but if you're a seller its an option.
If you're growing a tgp / mgp, i would recommend choker or
fpctraffic. You can get 100K uniques for 300 bucks at fpc and i think about 285 with choker.
If you use epassporte choker is also a good option. You just upload some cash to your credit account with choker. Wait for it to get approved (quick usually), choose your traffic, choose your hourly force, and bam you have visitors.