I recently bought @ 25lbs of cured LR for my wife's 29G from a local coral farm and have TONS of hitchhikers from his coral grow out tanks on my rock. I have green sponges, pink sponges, various worms, little snails, microstarfish, and...unfortunately, aiptasia.
I think that if you want good cured rock, you have to be willing to do a little bit of driving and research with your LFS. We drove from Canton, OH to Columbus (about 2 hours) to get a second batch of rock from this place as I found that the first 2 pieces that we got for my 55G were great.
For people in Ohio, look for saltwater and coral stores in Ohio (New Albany...near Columbus) through a google search. This place was by far the most informative, reasonably priced, and friendliest place I have ever been to purchase anything for my tanks. It is WELL worth the drive for my wife and I!!!