We sailed on Summit a year ago and liked it so much we decided to book again, this time with stops in Barbados, St. Lucia and Antigua. When we booked, we didn't realize the ship would be a week out of drydock so we were looking forward to seeing the changes. The bottom line was that the ship has changed little, except for more restaurant options. As a matter of fact, the "Solsiticization" totally overlooked cosmetic changes that would have had a major passenger impact.
We love the T-Pool and it was as good as ever, but the signs were never changed. They were old and worn out in places. The same was true in our stateroom. There were signs in the bathroom that may have been original to the ship and totally worn down. Minor things? Absolutely, but these are simple cosmetic upgrades that would have meant a lot to the overall experience.
We are Diamond Plus on RCCL so had Elite status on Celebrity. Embarkation was disappointing. We arrived about 12 noon and had to wait. There was no separate waiting area for Elites and though there was an Elite Check in Line which opened later, it was as fast (or slow) as the regular line.