I was all sold on tankless, but the one we got had a new tanked, and I'm pleasant surprised by it
No engine heat, but if I flip gas and electric both on, I've taken a half hour shower before. It wasn't scalding, and the water pressure was pretty low, but it was OK. Even with just electric, the wife and I shower back to back no problem. Having experienced it, I don't think I would go tankless.
That said, depends on your use case. If you are primarily a full hookups user, tankless is the way to go. My favorite places haven't been full hookups
1983 Airstream 310 Class A Motorhome