Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
I actually got an e-ink kindle before I discovered the original iPad mini. I tried converting my pdfs for it, but it was hit and miss, and some of the more equation-heavy documents caused it to crash. The iPad works much more smoothly, even if it's not as easy on the eyes.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.