Just to share my experience.... I'm sure any system is going have some quirks and limitations. That being said, I looked into 3Shape, and I ended going the Medit & Exocad route. I just felt that the more open the system, the more options I will have. With the openness of these, (and finding good support...which is key!) I've been able to find ways of getting things done, both simple and complex.
As for the scanner, I have been very pleased with the value, design, and ease of use. I hardly ever need the use for scanning spray. For abutments I can just do a light sandblasting ( staying away from the interface, of course ;-) I found no need for spray. For removable tissue areas ( I use Zhermack Gingivast Rigid) and it scans just fine w/o the need for scanning spray either.
As for exocad, (after the learning curve) I've had very few problems with design and I'm able to get milling done at places of my choice. I've had very few problems with any the updates as well.
Do some research, Give 'em all a test drive, and decide which will work best for you!
Just my HMO!