I think that you pay before they ship the tank. When ordering you pick the date and location that they will be at a trade show within reason from your location. You still have to pay for shipping to the trade show. When I researched it I would have had to drive for an hour to pick it up and pay over $100 to have it shipped there. They also have shipping via truck right to your door. For me, Craigslist was a good option 8)
My experience with them was positive. I ordered a 67G glass tank. The glass is 1/4 inch thick - doubled layers around bottom and top side edges. Center brace is also double layers. I had to scrape out some silicone that was a bit sloppy, and the trim isn't very neat at the corners, but my tank is in wall so that isn't really an issue for me. The tank is very, very sturdy however and I had no issues with the people there. They were quite helpful to me. I met their truck at a local truck stop and they pulled the tank off the truck and loaded it into my van. No gripes here.
I recommend them highly. You pay for the tank up front, and I picked them all up at a show in Raliegh, $40 bucks for delivery to the show from their place in TN.
They could be a bit better on the phone, very business like, direct and to the point. They upgraded my last two purchases (125 to 135) for free when they ran short on the availability of tanks.
I recently purchased a 125 gal Tall tank from glasscages. The person taking the order was courteous but business like. You need to understand exactly what you are requesting. I had the tank delivered by glasscages. Arrived as scheduled and after four months is still functioning. The workmanship could be better, with regards to sealing and bracing, but still a good tank. Take your time and ask the customer service department to work with you.