Quarteira and Vilamoura
I actually stayed in Vilamoura (moorish village) which is basically merged with Quarteira. The difference is that Vilamoura is simply a maze of resorts. It is a very posh place to stay and if you're simply looking for a lux vacation this is a good choice. It is beautiful in its own sort of way, but I'm not a relaxing on the beach kind of girl so I got bored quickly (also the water was COLD).
There are lots of "high brow" activities available, especially golf. If we weren't so embarrassed by our golf skills, we may have chosen to play. Fortunately, a bunch of the resorts (ours included) off special discounts to the golf courses for staying at them.
You simply will not find a true Portuguese experience here. I don't think I saw many Portuguese people outside of workers in shops and hotels so I would not recommend coming here to have an authentic experience.
However, as I mentioned before, it is truly luxurious and if it happens to interest you and you are just looking for a place to go on Holiday and relax, this would be perfect. I would compare it to me traveling to Florida from my home city of Philadelphia for a vacation.