Agree with Rob. I will eat rambutan and enjoy it. But if lychees were on the table as well, I'd go for them. I have come across some very tasty and sweet rambutan in PR. Juan has a seedling that was incredibly sweet and flavorful. Ian has a couple of really nice flavored ones as well but his yellow is by far my favorite. Of course, these are all right off the tree.
I thought a lot of the rambutan coming into the states was from Guatemala...not sure if they have to irradiate or not.