I like it. I alternate between Colistin and Tobi (I have the same problem with Tobi from time to time, like today <img src="i/expressions/face-icon-small-frown.gif" border="0"> ) when I have a flare up (Tobi for one flare up, Colistin the next). I believe it is also supposed to help fight resistance (according to my nurse several years ago when I started it). It doesn't "kick p.a. butt" quite as dramatically as Tobi does for me, but if I take it with an oral antibiotic, it seems to ratchet it up a knot. You can also get it in generic, which for me is a lot cheaper copay. I hope you like it too! <img src="i/expressions/face-icon-small-smile.gif" border="0">