I have mixed feelings about Hotel Club del Mar. Our room was "nice" but we were promised ocean view and we could barely see the ocean through the trees from our 2nd floor room in the main building. We were too tired to ask to be moved so it remained a bit of a sore point throughout our 4 nights there.
The food was definitely mediocre and the breakfast (continental included) was a real disappointment. They served a modest sized plate of various fruits. I would have preferred to have chosen my own fruit. It also came with 2 thin slices of "toast"... barely toasted and so cold that the butter wouldn't melt on it. Dinner tasted like it was heated from a package.
The service was great, especially at the front desk, where the staff were very friendly and helpful. The grounds were tidy, the pool was great (definitely a bit too warm!) and lots of lounge chairs.
I personally thought the beach was pretty nice. Yes, it was rocky near shore but we were usually out there when the tide was out so it was beautifully sandy to walk along. We found it to be an easy way to walk into town to shop a bit. It's NOT a great swimming beach due to the waves and rip currents. I stayed near shore and enjoyed the waves that crashed over me.
I didn't realize (until reading another review just now) that there is a concern about crime. We walked the beach after dark, walked along the main drag in Jaco and took a taxi back... no problem. In hindsight, probably not a good idea.
All in all this was a good hotel for the price and I'd stay there again... but would insist on an ocean view next time!