After going back and forth on various threads, I ended up replacing my substrate yesterday with Black Diamond. Here's a quick pros and cons list from what I have experienced working with it:
* Cheap! Over half the price of store brand "black sand" (Petco).
* Easy to maneuver into place. Doesn't melt into a slop like pool sand.
* Looks great!
* If you are handling it dry, it feels like fiber glass against your skin. I got very itchy very quickly, and even had to pull a piece of something out of my skin at one point. Once it gets wet, this doesn't seem to be an issue though. I dug around in it for hours with it wet without any irritation.
* Dirty! I tried cleaning it with a pillow case and hose but the water ran clear, I figured it must have come pre-cleaned. Once I dumped it in my tank though, the mess in the water took a long time to get cleaned up.
Here's what my tank looks like now (until I get more plants). This is the Fine grit. Yes, I do have fish in there, they are just hiding