I have tried the FDB after reading how people whose opinion I respect were raving about them. I always look to use the best food with the least mess and waste, the blackworms fulfill that challange and more. I am currently feeding them to my discus and angelfish, they attack them like no other food I use including FBW and Tetra Pellets and Angel one flakes. The food is very clean and does not foul the tanks. Most important of all is, the fish are growing so well on it and color up and try to spawn like crazy. I use the cubes because its easier and cleaner for me to just throw in 6 to 8 cubes per 55 gallon tank. Thats about 8 to 10 discus per tank and they all have full bellies with some left over for the Pleco's.
Summing up, easy to feed, a little goes a long way, fish love it, great growth, health and color.