has anyone had experiance with topsider homes?

We use only urethane and have built walls, roof, and floors. No experience with Topsider, though. Regards.

I have looked at them before , they like to use a lot of octagon shapes , which are terrible for useable floor space

Sorry for the late response.  Yes I do have experience with them.  I contracted a house delivery from them for the caribbean.  The beauty of the system is that the walls really have no load bearing as the frame takes up the load in a post/beam type construction.   My property was steep (2:1) and the pedestal design saved me a very large foundation.