Since you are just coming in one-night pre-cruise, I would opt to go with the least expensive, within a short hop to the cruise pier, in comfortable surroundings.
My suggestion would be to check out the rates offered during your vacation at the Radisson Ambassador. We were there in late April/early May. The going rate was $129 plus tax. Breakfast rates were reasonable for San Juan... but there are all sorts of places to eat along the Conadado.
I liked the Condado Plaza.... but the rates are generally sky high......and I'd only pay them if I were staying in San Juan for a vacation.
The Wyndham " El San Juan" is one of the highest rated properties on the Condado in PR. The Wyndham in Old San Juan is right across from the pier. Although the Old San Juan property is very convenient for one night pre-cruise, it tends to be expensive with small rooms. The ESJ Towers is next to the Wyndham El San Juan and may be a little more reasonable right on the beach. For Nov. 9 one night we got $160 at ESJ Towers and the Wyndham El San Juan when the regular rate is $290 at El San Juan.
You should definitely stay in Isla Verde; there is virtually no beach in Condado. The El San Juan has a one-of-a-kind lobby which provides great people watching. It also has great restaurants, including a very good open air Mexican restaurant on the roof with a great view and great margaritas. There is a great sushi restaurant as well. Unfortunately, most of the rooms are only so-so. They do have some excellent, huge rooms with beautiful baths, called Ocean Suites, which have their own private pool. If you want to splurge, this is the way to go. Intercontinental Hotels recently acquired the San Juan Grande next door to the El San Juan and it is also very nice; in fact, its average room is nicer than the El San Juan. It is undergoing renovation (which should not affect the public areas) and is probably offering some good rates. Whatever you do, go to Picayo for dinner, in my opinion the best restaurant in San Juan.
You might also like to check the Inter-Continental San Juan. It is also in Isla Verde next to the El San Juan. It was highly recommended to me by someone who recently stayed there. I got a very good rate for late Nov. You can check pricing on-line at their site. http://www.inter-continental.com
I've stayed at The Mariott Condado & had a great time.(last Sept) Very nice/Awesome restaurants within walking distance/Fantastic pool w/ swim-up bar/ nice casino etc. Highly reccomended by me -just my