Fair enough where the picture is concerned but they definitely do not clean the same IMO,the Xline all be it a good brush as well as the Gardiner is still to heavy. I don't think there is an argument for the supreme brushes some on here have said they like them I do not,those same people have also said they can't tell the difference between an extreme brush and a standard superlite so I don't think I'll be listening to them anytime soon eh.
I agree there is more to a brush than its glossy bristle feel - the design, layout, density, diameter and length of bristles all make a difference to the way the brush works on the glass. This does allow for great variety, which is good as there are many different preferences in window cleaners.
I would agree that the Supreme brushes are definitely not for you and I wouldn't recommend that you use one. I know from our past communications that you prefer a much more compact splay, in fact virtually no splay, to suit the high proportion of historic, leaded and sash windows that you clean on your rounds. I would say that probably no-one else has the same window types in the volumes that you encounter in your work.
Personally I think that the new Super-Lite Compact or even the Ultimate would be better suited your work than a standard Super-Lite or a Supreme. I have a feeling that the Super-Lite compact will gradually replace the zero degree Super-Lite brushes from our range.