I really love the polished alumide. It has a great look and feel, and holds up to a beating pretty well. I like it for test prints especially, though it can be trickier to get a print to work for that than the metals. Looking forward to seeing that black version...
I use Frosted Ultra Detail for molding masters for my miniature figures. I like it for it's fine detail resolution. If only surface quality were more consistent. Sometimes it's overly rough with little 'stalactites' that take a great deal of time to clean up.
White, Strong and Flexible would be my choice. I have gotten into making 3D printed costume accessories, specifically right now horns and head-worn fashions. The stuff out there at the moment is so heavy, out of paper mache or cast resin, it gives me the worst headaches to wear. I turned to the wsf material because it can be very thin, yet still very strong and very lightweight. I can produce hundreds of different designs rather cheaply and people with no craft inclinations can just paint them and go.
White Strong Flexible has obvious advantages in terms of cost and durablity for more utilitiarian objects. I would love to see solution died options (as opposed to post fabrication died). Other high strengh plastics (like Acetal) or even aluminum prints would also be cool.