These guys were great.
First off the process to enroll is simple and secure. Payment handling done through paypal.
Second off, the skill level of the booster was on point. I consider myself a pretty decent player with well over 1,500 games and played HOTs since Beta. The booster was able to get me out of MMR hell to a playable rank going at pretty much a 80% win rate.
They also have great customer service and respond promptly via skype or other options.
:handsdown: I'll give them 5 stars and will be returning to them for other services offered such as coaching and team league. Not to mention they have a great blog which is actively updated with patches giving out free information on strategies and tier ranking!