Even though I've had an offline conversation with Edson I thought I should respond here too.
I actually do still read things here because even though I may not work in CAD s/w any more I do enjoy using it... SU in particular.
I left IMSI because of a great new offer, not because of anything at IMSI -- they are still making progress as was seen with their DoubleCAD v3 launch.
Their forums, http://forums.doublecad.com, are a great spot to get quick responses -- they monitor them carefully, and take customer feedback very seriously so speak up over there if you have requests and opinions.
- Mac has been an ongoing internal debate, I don't know their plans now.
- IMSI/design does have very good educational pricing for the Pro (and XT is already free).
- I believe the general email is CustomerSupport@ imsidesign.com (or CustomerService@ -- I don't remember which).
- TurboCAD and DoubleCAD are both built from the same code base, but diverge in UI and feature sets with different intended audiences. But for the best answer to that question I would refer you to IMSI at their forums.
Give v3 a try and provide them with a lot of feedback (good, bad, etc) on their forums!
William