I was just in Tamarindo for two weeks in January. I dove with Aquacenter diving in Playa Flamingo. The Catalina islands are where just about all the dive shops in that local area go to. The vis is not the greatest, but we saw some pretty great things I think. One day we saw several large Manta Rays. Two on the first dive and two on the second dive that day. The next day we say another Manta Ray, it pretty much hovered over us for half the dive. Pretty amazing watching an animal like that stay so close to us. Also saw some white tip reef sharks, a sting ray down at about 90' with a tail that seemed to be 5' or 6' long. Schools of eagle rays, puffer fish, angel fish, eels, octupus, and lots of other amazing sea life.
By far the coolest part of the diving for me at the Catalina Islands were the huge Manta Rays, and white tip sharks.
The visibility was around 20 to 30 feet, and temps were 78 degrees near the surface and 73 degrees was the coolest I saw. 3mm wetsuit was suitable for me. And most dives were about 50 to 65 feet. I did my Advanced Open Water Cert while there so one of the days was the deep dive, thats where we saw the big sting ray.
The Bat islands are frequented during the rainy season, when the winds are a bit calmer than the dry season there. Apparently the seas can get unruly and make for unsafe conditions at that location, so plan accordingly if thats where you want to go.
I don't necessarly think Costa Rica is the best spot for a dedicated dive trip, but with all the other awesome stuff to do, the volcanos, beach, jungle, very nice people, restraunts...etc, it made for a great vacation. My wife and I are definatly going back.
Check out Nibana in Tamaringdo for good hapy hour drinks, and El Mirador for a nice dinner with a great view of the sunset. Most places in Tamarindo have 2 for 1 deals during happy hour which seemed to be 5:00 to 7:00. Find a fishing charter and do some fishing, we caught a bunch of Grouper and Red Snapper. Made for some good dinners.
