I know where you are coming from. DAZ has a different business model and it makes me unsure which way they are going to jump with their modeling apps.
I have Silo but it doesn't seem to be going anywhere at the moment. Very slow development and the V2 re-write seemed to cause a lot of issues. I'm sure they will fix them eventually. Less tools than Hex. Not really used it since Hex got symmetry.
Hex is still a good modeler as long as the changes DAZ make don't impact your work flow and you can live with the fact that content is their primary business so the tools are likely to be developed to support that. I've installed the update and I'll use it when I need to.
MoI is also good, but it is nurbs, no polygon modeling. So it isn't really a substitute for Hex, more of an addition. There is a bunch of stuff missing at V1 (no ways to organise or name things) but it is really stable and easy to use. Michael is very supportive of his customers and I reckon V2 will be a killer application. Plus MoI 3DM files go straight into Carrara (Pro) with no bother.
However, I have gone the same route as dooki - just bought modo. On Mark Bremmer's advice I bought the In Focus pack and I've been trying out the demo for the past few weeks and I really liked it. It's got loads of cool tools though it's more expensive and the learning curve is higher. But there is loads of training material available.
Only you know which one is going to be best for you. as always - try the demos and see which one you like best
