I got Modo...then got Silo because of Fugazi1968's nice tutorials, and kinda kicked myself for spending the dough on Modo. Now I go back and forth between them; but Silo is my go-to startup modeler. I like it a LOT and it's a bunch of bang for the buck!

Sale seems to be off again now, but it's a damned decent price for a good little piece of software. I think these sales are a yearly thing.