I have been using rio power flex leaders and tippet for all of my fly fishing. Recently I have noticed that they fray easily and don't straighten very well, making my dry flies look pretty unnatural (a few inches from the fly, it gets crinkled from knot tying). Does anyone know of any better product? I've heard the build your own leader suggestion but I'm not sure if I'm comfortable with so many knots.

i have always used Umpqua leaders for trout and haven;t had any issues.  If you are seeing the crinkling near the knot it is most likely because you are drawing the knot tight too quickly.  Take your time, use lots of lubrication and it should go away.  You may also want to try straight leaders as well.  I know for any weighted flies i go straight leaders and have no issues.  

iYou may also want to try straight leaders as well..

What do you mean by straight?

Not tapered, just a straight piece of leader material