You'll be extremely happy with either one of them. They have great personalities although they can be a little timid yet are very hardy. Hopefully, you have a deeper sandbed so they can excavate their cave/hole where they'll spend a lot of there time hovering in front of. At around $25, you can't go wrong with the pearly jawfish. There's even been some successful breeding of the pearly. Some places in Florida (if you're into internet livestock sales) will offer mated pairs which is kinda cool even if you can't get 'em to breed. I have kept both of them in the past and have been extremely pleased with how hardy they are and how well they eat. They might rearrange the bottom of your tank a bit so be prepared for that. I had one gather all the empty snail/hermit shells and create a cave masterpiece! Final thought -- a must have for a reef tank if the tankmates aren't big bullies.