I can only say I fully agree, I cannot live without it, and I cannot imagine how people use a wfp without it! Water going everywhere, even if you use a hip valve. With this, it's off in a split second, heck you can turn flow on and off between georgian panes if you wanted too.
Every time I use the SL2 with a valve, I find it a fiddly pain.
The Numatic George trigger is in my opinion the best. No sore fingers or anything, it's perfectly ergonomically designed.