My first attempts at sub-division were with the Silo trial (version 1.3) but I ended up getting Hexagon on release. I don't regret the choice, finding Hex much easier to learn and with some great line and surface modelling tools. Best of all is the dynamic geometry. I also prefer the interface to Silo - but that's a personal matter for you to decide. On the other hand, Silo does have some extra features that Hex doesn't, most of them are minor to me except for the topology brush, this may yet sell me the program - if I ever find my modeller's feet that is. The other plus with Silo is that it is a product in development, what you buy will gain new features at no extra cost (until version 2) - with Hex, what you see is what you get.