So has anyone experienced any problems with this lens?
I've not had the greatest dealings with Sigma, so I don't want to get it and have to deal with more Sigma problems!
Unfortunately, yes, a lot of folks have focus problems out of the box. Mine was horrendously bad front focusing on a T2i. But everyone on POTN that I've seen that has sent theirs in for calibration gets it back and loves it (including me). I guess you'll have to weigh your dealings with Sigma against how much you want the 30mm! I love mine and wish I could get out and use it more.