Well, a solid surface showerpan is the least likely to leak, but when you start going into custom or very large sizes, you may lose the savings factor.

A lot depends on your local labor market. We live in a very high-cost labor area so tile becomes one of the most expensive surfaces to install for large or complex (design-wise) showers.

A properly installed tiled shower floor shouldn't leak, but of course, the key words are "properly installed". Really good work is never cheap.

With solid surface, the installers just have to measure correctly and have enough hands to carry the pan in. It took three men to bring in a cultured granite 42" neo-angle showerpan!

dancingqueen: "Is a solid surface shower floor better than another tiled floor? I believe I can have solid surface made to the size of the new shower. Are they easier to slip on since they do not have grout?

There are two questions inside your single question: (1) what is the best substrate, and (2) what is the best shower floor.

Underneath the floor that your feet will be touching is a pan of some sort -- in older homes, a sheet of (usually) lead; in newer installations, usually a layer of plastic of some sort. Those are seamless and (for all intents and purposes) impermeable. If they will leak, they will leak at the margins only.

On top of the substrate is the layer that your feet will touch. When we re-did our shower a few years back, we put a layer of liquid sealant (a Laticrete product used in swimming pool installations) on the substrate, then applied some nonslip, rough-surfaced, Korean made 4" square porcelain tiles atop it with epoxy grout between the tiles. Completely waterproof, and as nonslip as one is likely to get in a shower.