Hi guys,
I've been using Kolinsky-Rotmarder brushes for several years, purchased from Feldherr or da Vinci and that has carried me through painting for many years.
However, recently, I've started to experience very poor brush quality, with tips that split after just a few brush strokes and brushes that don't keep their shape. What the hell is going on? Anyone else experience problems with brush quality - and if not - what brushes are you guys using and would recommend?
Doing some research online it seems that even high end very expensive brushes can turn out to be subpar. Is it due to shortage of Kolinksy-Rotmarder hairs on the market that we may end up with cheap copies of lower quality?
Drives me mad trying to paint my stuff, detail work is almost impossible and everything takes twice the amount of time as I have to reshape brushes after just a few brush strokes. Even repair gel and the like does not seem to work

Thanks in advance for any tips on alternative brush brands.
PS. during my last visit to an art store I saw brushes that mixed synthethic and natural hair, anyone tried these type of brush?