I had the opportunity to go on two cruises this year, both of which were with Celebrity. The first cruise was in the Mediterranean on Celebrity Solstice and our second was in the Southern Caribbean aboard Celebrity Summit. The decision to sail on Summit was based almost completely on price as we were much more price conscious for the second cruise.
The Ship:
Definitely not comparable to a Solstice class ship but the recent renovation insures the ship remains competitively elegant. Decks 2-5 are done particularly well, however, the main dining room feels outdated and extremely antique. Our cabin was well layed out and made excellent use of the limited space. I wouldn't recommend getting a cabin on any floor below seven as an off-putting sewage smell seemed to lurk the halls.
Great use of space. The hall is pretty private and no cabin is present on one side which makes the location very quiet.