I have this with with all the extra attachments, the V groove, the 45, and 90 cutters. You need to keep your blades fresh to keep a clean cut. You can cut thin stuff in one pass with enough pressure and a sharp blade. I use a cutting mat with it.
Use use Foamwerks. However, there is a slight design problem. The blades are held in place on a single post which creates a pivot point. Eventually the blade will dig into the plastic and the plastic will get cutoff and won't hold the blade in place. They should have used a two post method. Other than that it works great.
Well, if you can find something the blade won't cut that you can glue onto the piece of plastic the point of the blade is touching then you could prevent it. If I remember I will take pics of the problem.