Stayed at the Sheraton Algarve in July for 5 nights with my wife and two daughters (15 and 2). Wish we could've stayed longer!
Upon arrival, we were upgraded to a two-level suite. Master bedroom, bath and two balconies (one a Romeo/Juliet w/ double doors) upstairs. A bath, living area with pullout couch, small dining area and balcony downstairs. The accommodations were not nearly in the same class as say, The St. Regis Monarch Beach in terms of comfort and luxury. The Algarve was rustic, however it fit well with the surroundings. A little renovation wouldn't be a bad idea, but not totally necessary.
The grounds were beautiful. Two pools, equally used by adults and kids. The resort as a whole was extremely kid friendly, which was great for us. The views over the Atlantic were gorgeous, especially at sunset from the outdoor bar overlooking the cliffs. The beach was excellent. Good thing they have an elevator going down about 5 stories down the cliff.
As for dining, the aforementioned bar and the beach club afforded outstanding views. The food could have been better- especially for the price. For cheaper dining alternatives, check out the restaurants and cafes just outside the resort. If you want to go into Albufiera, that's another option. Basically anywhere is cheaper than the resort, but resort dining is certainly convenient.
My wife and daughter got good use of the business center to check emails, etc. Overall a great stay, wish I knew then what I know now... I would've stayed a few more nights. I'd like to go back, but there are too many other places to go in the forseeable future.
My ratings: Scale of 1-10 w/ 10 being best:
Room: 7
Service: 8
Food: 7
Location: 9
Activities: 8