I started using the Beattie screen out of curiousity. There were just too many positive
write-ups about it when it first hit the market. So I found an excuse to buy one just so I could find out how good it performed.
To go to the extreme, I bought one for my 4x5 camera. View camera users will know how dark and difficult it is to work with glass screens. After I got the screen installed, all I could say was "oh my God". The difference was like night and day!
Since then, I had the screen installed in my RB67 and all my Rolleiflexes and Rolleicords.
PS: I have not tried other 3rd party focusing screens yet. But there are heaps of praises bestowed upon the Maxwell screen from the users.