I really don't like to paint. I don't seem to be that good at it either. (chicken or egg?) I do understand the value of good brushes, and usually use Purdy. But, on a whim, I picked up a Wooster Shortcut trim brush. 2", angle cut, short flexible rubber handle. I really like it. Not enough to like painting, but certainly to dislike it less. Recommended.
It's kind of interesting that painters buy long brushes, and then hold them near the ferrule, ignoring that long handle. But actually, even though the length isn't used to grip, it does help balance out the weight nicely. Probably any decent Wooster brush would work as well, considering the fact that the bristles would be the same and you'd hold it the same way. A 2" holds less paint than a 2 1/2", but if the smaller size is more comfortable for you, go for it.