Hey: Where's El Tamarindo?
Cayman vs. Cabo:
Without knowing a lot more about what you guys are seeking, all advice should be taken with a grain of salt.
Here's the big differences between the two:
Cayman is very quite, lacks decent nightlife, expensive but also luxurious in certain ways. A great beach with lots of expensive watersports available. Awesome for scuba (so's Cabo), good food, little ethnic culture. Also, not very tropical compared to a lot of other places in that area.
Cabo is a full on party town. Like all of Mexico, rich with ethnic culture - but unlike the rest of Mexico, virtually crime free. Water sports are everywhere but as always in Mexico, a little shabbier than Cayman. Food's awesome if you like Baja cuisine and there's some more sophisticated places as well.
Both have golf but can't tell you which is better. Both romantic. Neither very tropical (Cabo is where the desert meets the ocean)