We (DH and I) took a direct flight from Boston to San Juan, and arrived on Friday. We stayed at the Sheraton in Old San Juan. I had booked a AAA package, which included a free breakfast; and I have a frequent stay membership account with Starwood (although I don't have a huge number of points), and I think the combination of both is what landed us a great room - 8th floor, overlooking the harbor! In fact I was able to check in and get our room key around 1:30pm! We had a front and center view of the Serenade coming into port on Saturday morning. Breakfast was a buffet, and the food was very good. I would definitely stay at the Sheraton again.
We caught the (free) trolley outside the hotel and rode up to the Fort, took some pictures and then walked to the shopping area. (I brought a 20% off coupon with me from COACH and got a great price on a purse from the outlet store!)
Checked out from the Sheraton at 11am, took a taxi to the pier, and stood in line until about 11:45 when RCCL started the check in process. By about 12:15 we were allowed to embark. We had a nice surprise when we got on board and were told our cabins were ready. Apparently the SOS was chartered the previous week, so there were no passengers disembarking before us. I guess the cabin stewards had plenty of time to clean up before the ship got to San Juan.
Hump cabin, deck 8, great location, convenient, typical cabin & balcony size-wise.