I have a love/hate relationship with my GMC.
It is cool and way-ahead-of-its-time design and engineering-wise. Relatively small outside but plenty of room inside. There is a near cult of people that are available to help maintain or upgrade pretty much any system on the coach.
But it is nearing 40 years old and there are many little projects needed to keep it up and running. The biggest hassle is undoing some very sketchy work done by previous owners (especially electrical).