I have TBS rock and can tell you from experience that the rock is terrific. I found myself rushing home from work everyday to see what might appear next, and something always did! I'd challenge anybody to find liverock with half as many sponges, feather dusters, beneficial worms, cup coral, clams, coraline algae, macro algae, barnacles, etc. Ofcourse you'll probably get some crabs and maybe a mantis shrimp also, but that just added to the fun for me. In fact, I just caught my mantis, and traded him at the LFS.