Escrow.com is the best, they are extremely fast, have great customer service, reasonable fees, and a nice interface. Most transactions I have with them are done from start to finish in three days, but I've had one completed in the same day.
The only time I ever use Sedo is when the transaction is over $5k and I need to pay with a credit card. Sedo makes you email them a request to set up a transaction which usually takes them two days if they ever actually do it, then every step in the process takes at least one business day, but usually two or more.
Haven't used Moniker yet, but I'd be interested to hear from someone who has.