I love love love polyester for quilting...but I learned to quilt from a real cotton purist!
I generally piece with cotton because of that ironing issue and also because nobody really knows for sure if over time polyester will be harder on your quilt seams...but for quilting, I almost exclusively use polyester. No lint and it comes in very fine or thick weights so you can create different effects and textures. The only real con in my mind is that polyester is a synthetic fiber...so in 80 years your natural cotton will fade but the polyester thread will not. If that is a concern to you, you might want to stick with cotton. I'm not going to be alive in 80 years so I'm quilting my heart out NOW without concern!