I agree with RainbowRuth. When I was little my mother owned her own business. When she started accepting credit cards there were alot of extra costs and fees involved. But it allowed her to make more sales. So even after adding in the extra fees she still made more money because of it.
IMO Paypal is way to convenient not to accept it. I won't buy from anyone that doesn't accept it. Whether the extra money goes to eBay or not it's a good service. I add in the extra eBay fees and Paypal fees to the starting bid price of my items.