If you don't like digging through frass to find all of the nymphs, you can employ this sifting method:
http://www.frogforum.net/food-feeder...phs-frass.html

I still believe its a good practice to have some control device on any heating element; be it for feeders or herps. I've seen melted bins that resulted from heating devices being left unattended. It's ultimately personal preference on risk assessment, I just don't trust anything that can potentially be a fire hazard.

Christopher - if you are good with dubia, I think you've got a nice chunk of information from everyone here. If you do go with the turkistan roaches, you'll definitely have to go with the ooth separation method if you opt for an aquarium unless you can cover the screen top with something to hold in moisture better. Keep an eye on molts too ; )