I've had quite the bad experience with PayPal myself. I used to sell goods on the internet. Nothing shady, unless you consider Wordpress shady. Anyways, one day I try to charge against my PayPal account and I find out my account has been frozen and is pending investigation. I had not a lot of money, but more than a few dollars.

It's been frozen ever since (about 2 years). I've tried working with PayPal, but they've yet to help me in any constructive way. If I were to add to this post, this is the reason I won't allow PayPal payments on my site.