i didnt like the extreme brush at first.in fact it felt like i was cleaning the windows with a toothbrush!!

but ive got used to it now.ive got a standard dt mono and flocked which are still excellent brushes and are used every week.
the extreme is great for maintenance cleans and the scraper on the brush comes in handy for stubborn birdmuck even if i can only scrub with the edge of the brush.
for first cleans i used the mono or flocked SL.more bristles and i feel like it cleans better.
the extreme is purely for regular cleaned glass IMO and it is very light so reduces strain even more.