pabl0rg: It's really a sum of bad experiences. Everytime I try to use it, I have problems with it. For example, it froze my PC from time to time, using as many threads as cores I have, and the option to disable multithreading doesn't work. It also keeps a deamon running, which often kind of locks and I have to kill it manually to be able to build again. The option to disable the daemon doesn't work either.
Finally, every time I tried to use it I switched back to maven afterward, everytime but one time: for an Android project. The fact that I'm not able to fully understand the build file of my Android project is a pain which just adds to the hate. It's messy and I don't even know why half the things are there, even after looking for it on stackoverflow.