Maybe I got lucky -- I got an excellent account rep when signing up for the API. She gave me a direct number to her desk and whenever I have a problem I call her and she fixes it.
I actually sent an email to PayPal's Executive Customer Service department telling them how great she was and how there probably wouldn't be so many paypal horror stories if they had more reps like her... and they wrote back with a generic apology for the problems I'd encountered.
During one month where our sales were particularaly high they froze our account too, but not for incoming transactions, so no money was lost.
I called them on the phone and was able to speak to a representative in 5 minutes who sorted it out. Not exactly a horror story.
I've had a couple of charge backs and those irk me to no end. Paypal always sides with the purchaser because software is intangible. I've been tempted to mail out postcards with the license code on them so that I can claim I sent something tangible out, but it seems like too much of a hassle to be worth it (it really only happens about once per year). I ended up solving the charge back problem in a technical way anyway.
I have no complaints about them.
The problem is that MOST people have success stories, but it doesn't make for a very good blog post does it? One sentence nobody wants to read.