In all honesty, if you are considering the Epic and you are single, I would go on Epic.
I do not know if you are an experienced cruiser, but I will assume you are not so experienced. I think you will find that Celebrity is not made to cater to younger single men. Your fellow cruisers will be largely older couples who most likely will have a short conversation with you at the most, but not get overly involved.
On Epic you have the studio staterooms specifically designed for solo cruisers like yourself. They have programs daily for solo cruisers and make arrangements for them to dine together every night. Celebrity does not do this.
Bottom line (assuming you are traveling solo) I really think you will find more company and friendly singles on Epic, and on a TA that makes a big difference - because if you get bored being on your own on Celebrity there you are for 10 days.