From my personal experience I like the 30s better...but there is a lot of bias for me on the 30. I've had 30s ranging from an 1800fom up to a 2000+fom and I had the UNS LR A2 (new 30) and a white 30 so I have a lot of hours on that platform.
I have never mounted the 27 on a rifle and shot with...