I've had a great experience with Retainers Direct. I've seen a lot of mixed reviews upon purchasing my retainer through this company. Shipping was very fast, and their customer representatives are very professional, quick to responding to any concerns and questions along the process. A lot of customers argue that it's a long process- it can be. It's very stressful, especially when you're worried about your teeth shifting. Be patient. I recommend ordering as soon as possible to avoid delays.
I will definitely be ordering again soon.