I don't believe I've ever eaten tilapia, so I can't say much about the taste. I have heard some negative things about farm raised fish, and I realize that here on this forum, with aquaponics, standard "farm raised" doesn't really apply. But can't we raise a myriad of different types of fish? What are people raising besides tilapia? I've heard that the South American Pacu is good eating. Are tilapia just really easy?
Kevin - My understanding is that tilapia are quite tolerant to varying water quality, so they survive well in farming situations. While I'm not farming my own, I do eat tilapia. It's a mild white fish, similar to sole but firmer. I find it to be very versatile. I use it for everything from Tilapia Almondine to Baja Fish Tacos. Whether or not they are the right choice depending on where you live. Not everywhere in the US has particularly cold winters, and many fish wouldn't tolerate the hot summers other places have. Tilapia are considered invasive in some areas so the powers that be won't allow their farming for fear they get out of your system.
The food source seems to be one reason. My understanding is that tilapia are opportunistic omnivores, making them a good fit for an aquaculture loop system. The fish fertilize the plants, the plants feed the fish (to a degree at least).