If you will be using Arikayce you need to go with the recommendation of your respiratory therapist, otherwise it's just personal preference. I have tried a bunch of compact units, and keep going back to my "Big Green" Pari Vios. My 7% saline comes from Walgreens, with my part B Medicare (since it is a solution used in a device, my copay is less than any online price. I prefer the Pari Plus mouthpiece, and order 2 at a time from whoever has the lowest price at the time.
Sue