I have purchased both of these and since I have recently bought a bigger tank I will be buying some more LR
soon but it really depends on what you are looking for. All of my rock has come from the guys at liverocks.com which I have hand picked since we live pretty close to them and I have found that the Gulf rock tends to come with more stuff on it. Stuff meaning anemones, some small coral, calcareous algae. The keys rock IMO
is prettier it is more of a bright purple and bright red while the Gulf rock is the darker maroon and darker purple. All the rock I have got from them is loaded with tons of inverts: crabs, shrimp, worms, brittle stars, snails, urchins ect. I think when I go back after their next harvest soon I will probably buy the Keys rock. Only because I have acquired a lot of anemones already and I have a FOWLR
so I love the pretty purple color. I hope this helps.