I believe that sometimes you do have to spend a little more to receive the good quality you would like, you do get what you pay for with a lot of things and considering I've used this brush every day since I got it, I think it was £16.50 well spent! I do think some of the other MAC brushes are ridiculously overpriced at £30.00 but thats just my opinion! I guess it depends on the quality, how often its used and how long it will last.
Have you tried any MAC brushes? Which is your favourite?