I've booked several times with Crucon and they are OK. They have good incentives (onboard credit, spa, etc.). The problem is that they are only open limited times and they charge a cancellation fee. We are probably going to go back to cruise.com. Always get prepaid gratuities and no cancellation fees.
Remember, Royal Caribbean/Celebrity don't allow travel agents to charge less than the advertised prices on their website (unless it is a group booking).
But you can get prepaid gratitudes with RC and Celebrity right? And/Or onboard credit?