I don't know what the new Mini one is like, but I have one of the original mills from when it was first released.
Mine is the standard metal one, not the SS, but as I use it and store it only in my garage, there is absolutely no rust etc on it at all, and still looks like new.
The best thing is the fact the rollers are geared, which means they never slip. The gap adjustment system is really easy to use.
I am more than happy with mine, and it will last me for the rest of my life.