all the way! I just bought a pair that fits(the pair I had before was too big) and the cotton feels incredibly amazing on my legs! I HATE the synthetic fabric from kerrits... or any other brand for that matter, it just doesn't feel right to me.
But everyone has different preferences for the kind they like, I've heard that devonaire and ariat are good brands for breeches. But may be a bit pricey. I would look for natural fabric, like cotton, when looking for good show breeches. Tan/beige/khaki are what they look for in the show ring, so I'd stick with those and save the purple/blue/pink ones for lessons!
I have these: On Course Cotton Naturals Classic Riding Breeches - Dover Saddlery
I like the classic cut better than the low riders for show.. if your shirt isn't long enough to reach you pants, you're outta luck when you have to tuck it in! And the price is fairly inexpensive compared to TS(tailored sportsman) or ariat.