This was our first time on the Summit and that may have had a lot to do with our expectations, but while the trip was enjoyable there were a LOT of areas that Celebrity just fell short. Our previous sailings were on the Equinox and Solstice so we have been spoiled. :-)
They have done a lot of updates to this ship, however it is definitely showing it's age with mold, pieces falling apart, and a general need of more maintenance.
The crew was a bit lack-luster compared to our other cruises as well with a lot of miscommunication I didn't expect. Had to wait over an hour to get seated in select dining the first night and they just didn't seem to have a well trained staff. This was the last sailing of the season so I would have expected them to have at least somewhat figured it out! This may have leant itself to the service as well though as they may have just been bored with the trip after running all summer.
The port at Bermuda and the entire island were beautiful and the snorkeling excursion to Devil's isle was great. This was booked through the cruise line and was actually quite nice. We went with the cruise for this as it was done on the last day and we didn't want left behind :-)
The other tour we did was through a 3rd party and it was truly amazing - highly recommend it to anyone visiting Bermuda. Bermuda Footsteps is run by a local that really loves the island and you can see it in how she runs the tour. Her co-pilot Buddy is her dog and she travels along on the tour which I really liked as we were missing our dogs while away. http://bermudafootsteps.com/