The Wooster Ultra/Pro Extra-Firm Cut Brush. Aw what a fine brush indeed. Our guys have been using this brush in the field since it came to the market a few years ago. We typically use the 2 1/2 cut brush for interior walls and trim, and the 3 inch for interior ceilings and exterior work.
Reasons why we use Wooster Extra-Firm brushes.
1. These brushes are nice and stiff, so they allow you to lay the paint off the brush just how you want it. This makes it easy to make straight lines while cutting into tough areas like the ceiling.
2. They hold a lot of paint. One major difference between a good brush and a not so good brush is the amount of paint that it can hold. If a brush is anything like the Wooster Ultra/Pro Extra-Firm it allows you to put more paint on the wall per dip, cutting down wasted time, and maximizing efficiency.
3. Finally, this Wooster series is durable. If you are nice to this brush, it will be nice back. Meaning, if you clean this brush every time you use it (like actually use a wire brush and make sure you get all the paint out), and don't leave it baking in the sun, it will be easy to use.
Personally, there are a lot of terrible / cheap / poorly made brushes out there. The #Wooster Ultra/Pro Extra-Firm cut brush is not one. I use this brush in the field and would recommend it to anyone.