I have been on about 3 or 4 rounds of Cayston so far. I like it better than TOBI since it doesn't take nearly as long to neb, which is awesome.
I did experience some negative side effects at first -- stomach issues & loss of appetite(maybe not related? idk), shortness of breath, loss of voice, etc.
Recently I have not had any side effects, so I'm still using it every other month. I don't feel any better on it, but I don't feel worse either, so I guess it's all good. My lung function has gone down since starting Cayston, but no way of knowing if it's just normal CF progression or due to something else. Good luck; hope you like it!!