escrow.com - totally unsecure for both buyer and seller, escrow.com verify "transfer" of the domain only via whois, which can be easily faked- from buyer or the seller. Cases of this type of scam has been several times reported here on DNF
afternic.com - unsecure for seller. They do as escrow.com, but also buyer has to verify the transfer. So if buyer change the whois back to seller and does NOT verify the transfer, he get money back and keep the domains.
The only safe escrow for both, buyer and the seller, is Sedo and Moniker ONLY. The fact, that so many escrow.com domain transactions have had happy outcome sofar is just that most of people are NOT scammers. So they actually could save huge escrow fees and just make wire + push, would be same level of security - none...