Only downside I can see to this model is, we don't always have on-site access to a water hose at comps. It's always there somewhere, but some venues require you to haul it in buckets/bottles from a "central" location. This one appears to require a direct hose connection.
We used a Coleman on demand heater for a few years, and still carry it as a back up. I've had a few issues with it, but none we haven't been able to overcome