I have found that PayPal really speeds things up. Since I tend to pay almost immediately when the seller accepts PayPal, I have found that most sellers appreciate the quick payment and ship ASAP.
There were some horror stories in the past, and there is even a website where people share these horror stories, especially those regarding difficulty receiving a timely response to e-mails. I did experience a little of that a year or so ago, but have found that eBay's acquisition of PayPal has helped things, even though the two operations are still separate. Also, using the 800 number and speaking with a real PayPal employee was also better than waiting several days for an e-mail reply. They have always been polite and helpful on the phone.
So, I would use PayPal before I would send a check or money order!