I have masterminds, not really because i'm a beginner, but more because i had no money. As far as i know they didn't change the core or any construction.
Anyways, I have them center mounted and I love them, they are super fun and buttery, and ski extremely close to my old t-halls IMO. They are great on rails and super quick and poppy. Great ski if you're mainly hitting rails. I do notice them being to soft or me on jumps, but you get used to it.
The durability on them has been okay, I've been skiing them since the start of January and I have a lot of cosmetic damage, a couple edge cracks and you can see signs of delam. But they don't seem that brittle.
Id recommend them, but not as a ski tha'tll last you more than two seasons.