Assuming that the GPL holds in court (in whatever country/state you're in), my biggest fear is that I wouldn't understand some part of it and get into legal tro

Assuming that the GPL holds in court (in whatever country/state you're in), my biggest fear is that I wouldn't understand some part of it and get into legal trouble. With a BSD or MIT license (or even just public domain) on the code you're using, you know that it's free to use any way you want. Maybe a bit paranoid, but with a large software project, you (or your boss) might not want to take that chance, and you'd be stuck buying a commercial app/library instead.