A relative gave us an older devilbiss pulmoaid for use as a spare. Duoneb (albuterol/atrovent) took less than 15 minutes -- would take 25 with the pari and tobi took 22 minutes while on the pari, it took 45-50 minutes.
Being new parents, we didn't KNOW that it wasn't supposed to take that long. Sure we read the info that came with tobi that indicated 20 minutes, but we had a brand new compressor... I turned around and purchased a brand new devilbiss pulmoaid.
With subsequent compressors, we've noticed that treatment times start to increase and the machines get noisier.