Hmmm a pressed CD is always preferred but I've not had any troubles with the Amazon CDR's so far. As far as being a "serious collector" ... eh well based on the size of my collection I'd say yes but, always am more concerned with the music itself. I don't mind iTunes or Amazon's MP3 store in some cases.
If the import is $20 not including shipping and the Amazon CDR is $12, I'm going for Amazon. Just have to be practical.