New to Hair Extensions

I have been researching hair extension techniques for the past two months online. I have found a few sights and of course each site claims that their product is the best.

I would like it if someone could give me feedback on the system that they are using. Pros and Cons.

The reason for my questioning is, I am a hair stylist and have always been interested in doing extensions but after reading some one the post on this sight, what I thought I found to be a great system, I have some doubts.

Also if anyone knows where there are classes for professionals and where I can purchase supplies I would appreciate it. I have had a particularly hard time trying to find ethnic or yaki pretipped hair.

Thanks in advance