I think there are advantages and disadvantages to the built in generators.
I added mine within about a year of when I bought my trailer new, way back in 2003. As of today, I think I have less than 200 hours on it.
Advantages:
Always have power and it is very convenient.
Less worry about theft.
With the right built in, you can run everything at once with plenty of power.
Mine is at least as quiet as the inverter styles - but only when they are under load. They are much quieter if they were just charging the batteries.
Disadvantages
Lose quite a bit of storage.
As mentioned, they use a LOT of propane. I figure on one 30 bottle per day if running the AC.
More expensive than buying or running an inverter generator.
If I were to buy again, I would skip the built in, and just go with two 2000 Honda's or Yamaha's.
And I don't think it is practical in any way to run the air conditioning without a generator.
