Windows Steady State software

I have been looking for a good, simple way to lock down about 20 mobile data computers so users cannot tamper with settings, access system files, etc. (a/k/a make more work for me). I recently came across Windows Steady State and was wondering what others’ experiences with it have been like. I have been using gpedit, however these machines are mobile and do not connect up to our domain so that makes them very difficult and cumbersome to manage.

From what I’ve read so far, most people are saying it is actually pretty good, but I am leary of the fact that #1- its FREE and #2 its from Microsoft.

I am looking for positives/negatives, tips, ease of use (or not), etc.

Thanks in advance.