Spark, Nomad and Traveler are the same design. Slow and noisy but no water needed to cool them and easy to store in a drawer when not in use. If I had a clean shop to work in and to store my gear in, I would go for the YH design. I do not have a clean hobby room and I need to clean up after myself every time I use my stuff. Don't expect them to live long lives if you constantly fill SCBA tanks. The small units are not designed for long runs.