particleman - 2:47 am on Jan 31, 2009 (gmt 0)

We have used WPP/paypal as our primary merchant for several years now. Knock on wood we don't really have transaction issues to speak of. UPS/USPS labels are very handy. Their API is pretty solid aside from IPN issues every once in a while.

My main complaint is their haphazard updates. It seems every time paypal makes an update everyone knows about it because something ALWAYS breaks. Usually on the website administration section thankfully, but it can be a real problem sometimes.