Terra clips are awesome. If you want reviews on each box, let me know. The maiden is wort making. Fat dragon games products are also good. I would do terra clips if you can afford it.....
I buy molds from Hirstarts and Merlin's Magic plaster and make my own. We have a nice group on facebook https://www.facebook.com/groups/44641935828/ and of course on the hirstarts forums.
I can't speak for other company's products but our 3D Terrain models are cast in our own stone formula that was created specifically for this product and are designed to last for years and years of play.