Hi Sharyn,
Coir is sold 'ground up', either in loose or brick form. So far, my experience has been good. My Miltonia and Paph are potted in it. Both are growing very nicely since the coir holds a good amount of moisture.
When using coir, make sure you mix it with perlite (a.k.a. sponge rock) for aeration. I use medium perlite because the fine/small are too small (for my taste, that is). Some people mix it with perlite and charcoal (which I don't have, yet). Since it's difficult to find medium and large perlite at local nurseries or big box stores here, I order them online.
Not too long ago, I started using coconut husk chips. So far, my orchids potted in it are doing fine. The advantages I see is that it helps with raising the relative humidity because it holds more moisture than bark. Living in a low humidity area, especially during winter and summer, the extra moisture helps. I read somewhere that coconut chips helps deter certain pests and lasts 3-5 years. That means less frequency in repotting, unless needed. (ok, call me lazy
) I either use it alone or with medium to large perlite, depending on type of orchid.
HTH.