We were just in a CS on the Apex a few weeks ago. We love the CS on "S" class ships, especially that big balcony in the ones on the hump. The CS on Apex was very nice, the balcony was fine, but much smaller and no lounge on it, just chairs and 2 tables. I missed the lounge. There is more than enough storage in the Apex CS but missed the walk in closet that the "S" class has. The bed is larger in the Apex CS and more comfortable than the "S" class. Bathroom is very nice on both, though they older we get the more getting into that bathtub/shower becomes an issue.
The Retreat areas are very nice on both, though we like the Retreat(Michael's)lounge on the "S" class more. I'm sure you will enjoy your cruise, but the Edge is a completely different Celebrity experience.