Started using GG4 at 20 - 25 mil + Sorbo Gluide at 10 mil today, and after squgeeying and a small amount of detailing at the top and sides think the products are amazing, i am the third generation of window cleaners in my family and am traditional, all i have ever used is fairy, which up til now i thougt was fine for the job, however i stronly recomend to every one traditional "Try This Product!" it doesnt soap up but after a few days you get used to that and you put far less pressure on cleaning the glass.
The soap drys almost clear and with a t-spoonful of sorbo i slides like a beauty, also you use so little of it it looks like its going to last for ages, so try this product, you wont be dissapointed.
P.S. Don't forget to buy the measuring bottle as well, its very handy and can be used as a handy hip flask for a whisky sorbo easy gluide type mix :-P i read the measurments off of Hitman on here and seems to me that he has got them spot on!