My sister and I are going for a quick for night getaway in early March. Primarily interested in R and R, and will go into Old San Juan maybe once or twice. pool and beach impt. As is overall room quality
Any recommendations between the two would be appreciated.
Thanks!

Are you referring to the Marriott Courtyard in Isla Verde or the Marriott Stellaris in Condado?

The stellaris.

I have never stayed at either, however, I have stayed at La Concha (near Marriott Stellaris) and El San Juan (next to the Intercontinental). The Intercontinental has a better beach but the Marriott Stellaris has more dining options in walking distance. Although, the Intercontinental has enough restaurants in walking distance considering you will only be there for 4 nights and I am sure you are likely to have at least one dinner in Old San Juan. If beach and pool are the priority, I would say go with the Intercontinental. Both hotels are easily accessible by taxi to Old San Juan. The Marriott Stellaris is about 15 minutes and the Intercontinental about 20 minutes (probably less actually). There is also a bus from both areas to OSJ but I have never taken it.

If you want to visit Old San Juan... stay in Old San Juan.

I just spent 3 days in OSJ last weekend and it was awesome.

We stayed at the Sheraton Old San Juan. It overlooks the San Juan Bay and you can walk everywhere you want to go in Old San Juan.

I'll give you a few suggestions for meals...
breakfast - Cafe Manolin on San Justo, just a few blocks from the Sheraton. You can eat for $3-$5.
lunch/dinner - Punto de Vista is literally one block from the Sheraton. They have cheap beer, 2 for 1 mojitos @ $8 and the food was excellent. You would be missing out if you don't try the mofongo. Most meals range between $10-$15.

The hotel pool is on the roof, but nothing special. There is a beach that is only a 15 minute walk from the hotel.

I felt very safe in Old San Juan, plenty of police around... I can't say the same for the hotels on Isla Verde.

I think henwoodc is right if you want to spend a lot of time in Old San Juan you should stay there. However, if your main purpose is to relax on a beach then I wouldn't stay in Old San Juan. Isla Verde is a nice beach area, as is Condado but the water is a bit rougher for swimming. I was in Isla Verde last week and it felt very safe. Isla Verde Ave had lots of people walking around day and night, at least by the El San Juan and Intercontinental hotels. We went to Old San Juan twice by taxi during our stay and it was very easy.

If you are going to San Juan for a short stay and the beach is important, then it's insane to stay in Old San Juan, which has no beach. It's very easy to take a taxi into Old San Juan for a day of touring and shopping and for a night of dining and drinking.

I agree that there are more restaurants in Condado within walking distance, but the beach in Isla Verde is much better. And increasing street crime means walking at night ... Even a few blocks ... Is not necessarily advisable any more. You're ok in Old San Juan if you stick to busy main streets, but take taxis everywhere else.