I use the Pari Trek S for my Xopenex and HS on occasion, and rarely for Tobi and Pulmozyme (the "something is better than nothing" theory) if I am running late and am going to be gone all day. If you get one, make sure you get one with a battery- that is soooo nice. It's also nice doing nebs in the car. I have been meaning to research the Trek particle size vs. the Proneb Ultra and Pulmozyme and Tobi, but I just haven't had the time yet. That's what you need to know- I've heard that the particle size is borderline, but I don't know via my own research. It isn't any faster, as a matter of fact, mine is a minute or 2 slower with a Pari LC+ (same speed if you use the Pari Sprint that comes with it, but you <i>can't</i> use the Sprint with Pulmozyme or Tobi, etc.). It is really convenient though <img src="i/expressions/face-icon-small-smile.gif" border="0"> .