While I can't speak at all about the properties themselves, I can speak a little about the location.
Le Méridien Dona Filipa is almost on the beach.
Le Méridien Penina Golf Resort is about 2.5 miles from the beach. (Free shuttle provided.)
You may also be interested in this website about the surrounding resort as you evaluate the Sheraton Algarve...
http://www.pinecliffs.com