Silo is a really good deal for the money, but personally I didn't like it. Nothing wrong with the software - it just didn't fit in with my way of working.

As a general modelling app, I think Modo is the best there is. The interface is so configurable it's hard to believe, and some of the tools are really powerful. My experience is that it makes modelling a lot easier (and this coming from somebody who freely admits he cannot model to save his life!).

It's not exactly cheap (unlike Silo), but having used both, I just prefer the way of working in Modo (and it plays well with Maya too!)

Version 2 is due out soon, also featuring 3D painting and what looks to be a super fast renderer.

Anyway, here's a couple of renders of my first Modo model (still to be completed, as I'm waiting for the 3D paint tools and renderer in Modo 201). These pics were rendered with FPrime running under Lightwave, in order to cut down on the time I had to wait for them (by about a factor of 3 over the default Lightwave renderer - god knows how long this would have taken using Mental Ray).