I have a quite generator, Boily Pro3600. It isn't much different than a Onan built in one for noise. Unfortunately, the standards for measurement are different.
The onan is 70db at 1/2 load at 10 feet.
Boily is 58db (much less) but measured at 21 feet. That makes a difference.
The Honda 2000 is about 59 db at full load, and I "think" also 7meters/21feet.
Not easy to say what they are rated at for only 10 feet like the onan.
AND, you don't have to carry extra fuel.
Sucks to have Diesel truck, gas generator, propane RV.
I mounted my Boily on the bumper, so anyone in the table bed is about 5 feet away.
However, I can move mine further away and use it for other than camping. It's pretty good on gas also. I threw in a remote start key fob and remote fuel tank options and it's working pretty good.
All in all, I think I'd still do the built in one on my next TC. I'd say the extra storage space of the empty generator compartment is handy!
Depending on usage, I can also go about 3-4 days with batteries. Then hit with the portable generator.