Amazing1 has been in business like forever (at least 30 years). The owner is an electrical engineer (Ph.D. if I remember correctly). They are resellers just like everyone. Their business is not about lasers but about neat electrical gadgets. Some of their stuff is fun and interesting. Yeah, they test their systems. Frankly, they probably have much better equipment for testing than some of the vendors. But remember they are not a laser resale shop. They are a general gadget shop. So make of that what you will. I've dealt with them on non-laser related business and they are a fine company.
Here's a bit of trivia. If you are a MythBusters television fan, the lifter anti-gravity device that Grant tested on the show (and the only device that actually flew) was from Amazing1. Of course, it's not anti-gravity, but uses ionized air to accelerate air downward to thrust the lifter upward. A fun, high voltage project if you like that kind of thing.