I have had rock from Caribbean, Fiji, Tonga, Kaelini, Bali, Marshall and I am sure elsewhere.
You are correct that the rock has tons of life. Some of it is quite amazing too. I remember one time seeing a little orange shrimp that I thought was too cool Ok, back to the topic, ahem, but the problem was that most of it died off and thus the cure time on the tank was huge as was the skimming needs even after curing. Also, the rock was quite dense relative to some of the South Pacific rock. So, you may find that the rock cost perhaps more than a similar amount of Fiji for example due to porosity. On my current tank, a 165 gallon, I used 120 pounds of Bali. So it cost more per pound, but the overall amount was less, and thus my total cost was similar.
The life on Caribbean is very cool. and compared to Pacific quite a bit better, but in my case, I want to know what is on the or in the rock rather than a mix as I would not want something dangerous to my sps, clams, fish, etc. Isopods, flatworms, fireworms, crabs, shrimp, etc can be dangerous.
There is very little markup in rock and my guess is most stores are paying around $4 a pound or so. This is speculation mind you, but our LFS provide us such a good service, I would encourage you to consider using them when feasible/possible as everyone is simply trying to make a living.
My new 600 is using Bali rock with a few branches of Tonga. Of all the rock I prefer this, although even this rock I make adjustments to fit my own personal tastes. I hae chosen to kill it all with interceptor just to be safe. But that is the beneift of this hobby, we can each have our own preferences and find the product that meets our personal tastes.
Kip