RFEM is the best I have used. I have experience with RISA, STAAD, ETABS, Visual Analysis, and others. In the tensile/fabric structure world, I've tried NDN, Forten, etc. Once you get used to RFEM's interface, it has no comparison to the others. Even with typical structures, it's much easier.
Fernando Peña, P.E.
President
Rocky Summit Engineering Consulting, LLC.
Irving, TX
USAwww.rockysummitec.com