It's an awesome place, my OH has given me the green light to take the whanau there, just got to save up the $$ to do it.
Last time I went, I stayed here
http://www.harborreef.com/ for a few days, it's a great spot, right on the money for some nice beachies, good food, good game fishing too, monkeys and tucans knocking around in the trees, bar in the pool etc etc. Definitely more than good enough for a family. Tamarindo is pretty cool too, but busier.
It was a few years ago that I went there, so could have changed, only advice I would give is be dead careful driving, or you could end up dead. Scarier roads than NZ there, which is hard to comprehend as being possible, I wouldn't plan to do any driving at night. It's well worth renting a decent 4wd if you want to do some exploring.
I let my dipsh1t mate book 2 4 wheelers for us, he thought he got a really good deal, but at 4am at the airport in San Jose, when we phoned the Hertz office, it turned out he had booked them for San Jose in the USofA. So we had to pay for some more and hang out at the airport for a day waiting for the rental place to open, which was a bit of a choker.
Great place though, one of my all time favourite places to head for a trip. Can't wait to take my kids there.