I've used it for years!  Probably since it was something like 0.9 alpha.  I'm glad to see it released to the public.  It is very useful and I like the syntax better than R (which I've been avoiding).  R has far more packages, but Sho is super easy to work with for random tasks and easily integrates with .NET. 

I wanted something like Matlab that didn't cost a fortune and found that MSR had this as an incubation project which met my basic needs