We will release a "for sale" version of Impression later this month. I can't give the exact date, but it is somewhat soon (hence our lack of participation on the boards right now as we are pretty heads down!)
The Technology Preview version will work until late April. When we officially launch Impression, there will be a trial version available for download. The trial will allow for 40 hours of use.
Product Marketing Manager - Impression
I believe Impression can add value to any designer's workflow. However, as an owner of AutoCad, Revit, SketchUp Pro and other similar programs I hope Adesk offers Impression at a 'reasonable' cost.
Right now, I see it's value somewhere in the SketchUp range but certainly not a player in the high rent district. Having said that, this is a simple to learn, easy to use product that fills a digital gap sorely needed. But if the cost becomes too high, well...back to the markers!