I have the 2.0 super shell, one of my ski buddies got the 3.0 at the end of last season. He is very happy with it.
As far as I can see, the main difference is it has the new 840 silveretta release mechanism that is more vertically oriented than the 750 on my shell.
One can retro fit the 2.0 shell with the 840 release - I am interested in that due to the stainless steel arms as I have a fair amount of rust on mine.
Visual inspection leads me to believe the heel cup is the same, and the boot itself is the same- just different colors, I was hoping they improved both over the 2.0 to eliminate a small amount of play I experience.
I sent in a question on this topic to reflex on their website (actual changes between 2.0 & 3.0) - no response yet.
While at ski paradise (which rocks by the way if you’ve never been) this Feb I got a close look at the latest version of the HO Syndicate hardshell, it’s impressively engineered - the boot fits into the plate like a glove - there is zero play when locked in. The HO has the same 750 silveretta release as the 2.0 reflex. Only advantage the reflex shell has is better ankle mobility and range of motion, the HO shell is very rigid in comparison.