I use Robert Simmons Titanium brushes. I'm surprised to read that people have been having issues with them. I love mine. They are so easy to clean and keep their shape and the paint coating on the handles does not crack. Mine are still like new after a lot of use (I do look after them and clean the handles regularly). The bristles are lovely and soft and flexible which I prefer to many of the stiffer brushes that seem to be out there.
I want to try some angled brushes so I have just ordered some of those from Rosemary and Co.
Just for anyone interested, Rosemary and Co have brought out something called a 'smooshing brush'. Anybody tried them? I might order a few.