The OP didn't seem to express a disdain for two wheeled models, just a heightened curiosity about trikes. +1 to www.bentrideronline.com where you will find a large following of both two and three wheeled recumbent owners. Most of the major bikes and trikes have reviews as well.

I'll PM you with my list of trike brands to consider and at least one to avoid from my personal experience and why I like the ones I like.