I think this brush thread is refreshing actually, since it has been a while since we've had a proper brush discussion. For the last several years I've been using E & J Gen X and Gen Y for nearly everything, but they are almost impossible to source anywhere. Before that, Wooster Alpha was my fav for years. The Gen X/Y's will do everything the Alphas do, but they'll do it a little better, except for Alphas being able to hold slightly more paint.
Lots of buzz on FB groups about Oldfields and Richards, but I've never tried either.
Corona has a few offerings that are ok, but not my fav. For me at least, they don't seem to hold their shape/form for long, but maybe that's because I suck at taking care of brushes and I always have. I need a brush to be able to stew in dirty water or wrapped in plastic & foil for a month while still being able to go back to work when duty calls.
I haven't really been a fan of Purdy brushes for at least 15 years, but I know some well respected painters who love them, so they must be doing something right.
I'm now relegated to Alphas again, as well as the occasional Corona and even Picasso. Good thing I don't do a lot of brushing, since I'm completely unhappy with the roster.