I just returned from a 5-day taste of the Crystal Serenity. It really wasn't enough time to truly get to know the ship, particularly as bad weather caused them to have to make some itinerary adjustments, and pull some things together on the fly. But it was enough time to get a feel for it.
I'll get to the bottom line first: I highly recommend this ship. Now, some details.
I don't mean this as one of those "cruise line X vs. cruise line Y" rundowns, but since Regent is my primary frame of reference, I think it might be easier to give an idea of the ship by using Regent as a comparison on some points, for those who have been on their ships.