Hi Tommy,
Shops and team riders writing reviews on new gear is the best and fastest way to get informatin about a product to the general public. Often the product will be a pre-production prototype so you'll get to hear a riders perspective before it is released to the public.
It (review) generally, is not going to lead to a sale of a kite, but may lead to the reader seeking out a demo ride. The demo ride is where the decision to buy is made. If the buying rider reads a review and finds the total opposite when demoing, then the reviewrs credibility is shot to bits and it's likely they wont make a sale.
Some shops/pimps write a bunch of glowing crap about poor products, it isn't too difficult to spot an honest review IMHO. Most of the time shops write the best reviews with the most detail. It is designed to give you an insight as to whether the kite may be appropriate for a particular riding style or rider so as they may seek out a demo.
If you look back at most of the reviews, the threads are started by shops/sellers which then invites other riders to comment or write their own reviews. At the end of the day, if you write crap and someone who is not affiliated writes a review opposing the original shop views, this will raise some serious suspicions about the reviewers credibility and the truth WILL come out in the wash.

The Kite Reviews Section would be pretty quiet if shops, team riders and pimps never posted thier reviews. You probably still wouldn't have heard of Core GT's

Good winds,