For me it 100% depends on the buyer. If it's some random yahoo address emailing me wanting to buy a domain, they'll be using Escrow or mailing me a check. But if I'm the one who contacted them, and they're a legit business, I'll accept PayPal because I can get a transaction done in a matter of hours. In my experience most buyers prefer to just use their credit card and be done with it, even when they don't normally use PayPal (they do not need to sign up to pay for an invoice). Some buyers take a few more days to pay than others but generally people pay pretty quick. In most cases, I personally don't force an established, legitimate end user to use Escrow unless it's a solid $xxxx sale.
I figure that if I'm dealing with a reputable business or businessperson, they would regret it real fast if they decided to pull a fast one on me. It simply wouldn't be worth the damage I could do to their name on the internet by exposing their fraudulent ways to the public.