I own a TruDef that I put into a surgical office to do implant scans. Works well for that as long as the operator pays attention to the seating of the scan bodies (not always the case - grrrrrrr).
I also have a C&B account. We do some model-less stuff and she seems happy with it although we are still dialing in occlusal parameters (@.31 reduction now and headed lower...) I don't believe you have to have a margin-marking laboratory if you have ModelBuilder. Just import the .stl fils and mark the margins inside 3Shape. You can go model free or send the models off to be printed. One potential hiccup is that you are getting unfiltered data, so if the scan has holes in it, ModelBuilder sometimes doesn't play well with that scenario. Those are the case on which I back up and send them to 3M to massage the data and output the model. I respectfully disagree with LabGuy - I personally don't like 3M models. They are a little too slick (surface texture) for my taste. I prefer 3D Systems PearlStone. You can get printed models froma variety of sources - Core3D and Argen have been good for me. (I have my own model printer which is currently down or I would offer to print some for you - sore subject)
Tru Def requires powder and you need to tell your guy there is a pretty significant learning curve although the new want is a significant improvement. I also just bought a Trios which is much easier to scan with, but you're talking double the price....