We arrived in San Juan a couple of days prior to the cruise (Southern Caribbean, visiting St. Thomas, St. Kitts, Aruba, and Curacao). We stayed at the Sheraton Old Town, and while it's not the classiest hotel on the planet, it's in a very good location and the rooms were clean, comfortable and reasonably quiet. We also took a separate tour (via Viator) of the El Yunque Rainforest, fairly near San Juan. Highly recommended. You can also book something similar via the cruise line, if desired.
EMBARKATION. The cruise really got off to a horrible start with one of the most inefficient embarkation processes we've ever experienced. We showed up at the advertised boarding time of 2pm to find 2 long lines. Neither of the lines were explained via signs and there was an absence of cruise line personnel to answer questions and help direct cruisers. We finally found out that one of the lines was intended for people with large bags to check, the other for those that had already checked their bags. Yup... that's their system. You get to wait in a VERY long line (hours long) to turn in your bags. Then, you have to go to the back of the other line (also VERY long) and wait again until you can clear customs, process in, and board the ship.
Naturally, many people had little patience for this and felt it appropriate to simply join the second line in the middle or front in order to reduce their time waiting. This generated a lot of tension as these line crashers obviously contributed to the line being far slower than necessary. What's more, many of the locals felt it appropriate to invite a huge number of their friends into the line, further slowing things down. Complaints to the very few cruise line reps present had no effect. Overall, the boarding process took us nearly 3 hours, and we were the lucky ones. We were allowed to turn in our large bags after having worked our way half way thru the first line -- then had to wait in the entire second line. Others who were not randomly selected had 4-5 hour boarding waits, some of whom missed the lifeboat/evacuation drill as a result. Totally unacceptable. Some of this is attributable to incompetence on the part of the San Juan immigration department, however, the cruise line did nothing to help sort things out and ensure that people kept their place in line. Our experience with Celebrity from the same embarkation port was far better a year previously.