Hi Playdo,

**What would you say is the closest software solution to the flexibility of sub-d modelling with the benefit of booleans? I never used T-Splines, but not sure what is happening with it**

FWIW, there's recently been announced another Rhino Plug-in called "Clayoo"
http://www.clayoo.com/

I've personally not tried it, but from the reports I've read, it's working in a similar way to T-Splines.
For those with Rhino & not prepared to now buy into T-Splines, this might prove to be a good option?

HTH, Colin