We loved being only 500 people with Regent, so were concerned about being with 2800 people on Solstice BUT with only a couple of caveats this was not as bad as we feared.
Embarkation was easy and quick. Dining in all but the Grand Epernay was sufficiently private, we found the tables in the main restarant too close together so only ate in it 3 times although food and service were excellent. We enjoyed the excellent Murano, very good Tuscan Grille, very good Silk Harvest, and relaxed Ocean View; and room service. There were always places to sit on decks, especially 14 and 15. The hot tubs (5) usually had space.
Our Suite wss large and comfortable, the service from a team of Butler, steward and assistant excellent and friendly.Breakfast on our balcony was a joy (except the occasions when the lady from New York was out next door with her terrible accent).
Our main issue would be the very long time it took to disembark in Dunedin where we had hired a private guide(we were 1 and 1/4 hours late). There was minimal supervision of the 2 lines and so everybody was pushing in. In contrast the tendering at Akaroa was well done.
Drinks are expensive, $26 a glass of champagne, $30 a glass of ice wine. We arranged our own tours except in 2 ports. We will arrange all in future as the price Celebrity charge enables 3 people to buy a local private guide not suffer with 40 Americans (we live here but en mass our fellow residents are not our cup of tea) in a coach. New Zealand is divine. If only we were under 30 and could emigrate again! Celebrity have a new customer.