If you're an Ebay seller, you pretty much have no choice but to process your sales through PayPal. PayPal takes 6.5% of the sale amount; Ebay takes 10% on top of that.
If you send money to a person or business, same story, 6.5% comes out of what you send.
A lot of businesses, especially small ones, won't except PayPal as a payment option because of this.
In short, there's no winning with PayPal.