I recently started doing some palladium/platinum printing and realized I needed to upgrade from my mainstay coating style--foam brushes. I still like foam brushes for cheap sensitizers, but the rapidly escalating prices of precious metals is making the emulsions much dearer these days--and foam brushes waste a lot of emulsion.
The Richeson 9010 (aka Magic) brushes are great, but if you want more than a couple, the price starts to get prohibitive. I think I've found a good substitute coating brush that has a lot of the valuable qualities of the Richeson--economical and even coating.
Liquitex Freestyle paddle brushes are synthetic brushes that absorb very little sensitizer when wetted, the flat bristles come to a nice thin taper, and the brush doesn't shed like a cheap Hake. They come in a nice range of sizes and a 3" brush costs $16.50, so they're very affordable. They're noticeably stiffer than the Richeson brushes, but I haven't had any issues raising the grain on paper as long as I coat with a light touch.