Some stick to moniker not due to personal interests but because of one simple fact that sets them apart from the rest of the escrow services.
Moniker is the only escrow service that is also a registrar, and during the transaction they take both the domain name and funds into their secured account. They hold the domain until they receive the payment and then they switch hands.
On the contrary, escrow.com receives only the money from the buyer and leaves the domain transfer to the seller. Even though I have never seen a scam like that, some have suggested that the seller is possible to complicate the escrow transfer by changing the whois records to the buyer's and then claiming that he has transferred it to the buyer.