I recently bought one of these brushes as a secondary brush to use while my favourite brush (Avon Daring Definition lining brush, which doesn't appear to be available any longer) is sitting to dry after being washed. Previously, I had purchased a lining brush from MAC that they specifically recommended for their Liquidlast eyeliner (which is the liner I use), but I don't care for it at all. After just a couple uses, it hardens to a gross, spikey mess with bristles sticking out everywhere and I end up with little splashes and speckles of eyeliner everywhere because of it. Then I came across this brush when it was on sale at Shoppers Drug Mart and decided to try it out. I really like it. The bristles hold together much better and I like that you can use it horizontally for a thin line or vertically for a thicker line. The only real complaint I have about it is (like the last poster) that the handle was too long. I ended up cutting half the handle off and now it's just right. I just couldn't stand having to stand so far away from the mirror to do my eyeliner just because the brush handle was too long. I've since bought another one of these and again cut the handle off, and they're working well in addition to my Avon Daring Definition brush.
I also agree with the last poster about the little plastic pouches they come in. They have the potential to be a good idea, but they're nearly impossible to open! You have to try to squeeze your fingers in there to try to pry it open and it's a real pain in the butt. On the other hand, I guess it is kind of a bonus that you even get a pouch with the brush so you can't really complain, and I'm not going to remove any lippies for the lousy pouch for this reason.