If you've got a family with kids under 5, and you're desperate for a proper holiday, go here. We loved it. It's fantastic. Go there. You won't believe the relief you feel when you're actually enjoying yourself.
ALL the staff were a delight to deal with, our kids ran into the kids club (they were that keen to return), our villa was large and almost too big, the main pools were fab, the restaurant food was very good (albeit the menu is limited, although in a mostly self-catering site, that's understandable). And the setting of Quinta Do Lago is immaculate and the beech and lagoon are beautiful.
The only issues I have are:
There is no proper kids playground (the trampoline, pool, van, sandpit etc are great, but a set of swings, slide etc are required to tire out your toddlers).
There's no gym.
The shop has a well-chose range but is very pricey... and thus empty. (Reduce the prices, and bingo, more customers!)