I am not sure which system I use, but I suspect the 'old' one. Certainly it's not changed since the early 90's when I learned SRT.
I am quite happy to stick with it because I am very used to it, and it's instinctive. I know exactly where I am.
For example, I am sticking with a Petzl Stop, because I think I am probably not going to 'panic squeeze' having not done so in nearly 30 years of usage. Even though there are probably superior descending devices that I might use if I was starting out now.
Furthermore, not everybody is in the same environment - I do most of my SRT in slate mines, often bolting up, so the requirements are somewhat different to vertical caving.
I am open to small changes however, provided they are not going to upset my built in knowledge of the rig. Hence following this thread.
Chris.