What scripting language is best with iControl Rest

I'll ditto Michael's comments. It depends on your platform. If you are on Windows, the PowerShell is a good choice. For non-windows systems, it depends on your skills. I'm like Node.js lately as has JSON/etc built in but you can use JSON packages in most of the other main languages out there (perl, python, etc).

If you just want to use a shell (sh, bash, etc) with curl, then the jq command line tool is pretty helpful in parsing JSON responses. http://stedolan.github.com/jq

Good luck!