I've posted it before and an extensive western trip has solidified my view. I have a 24' C on E450. In the 11,300 lb range.
Tow haul is great as needed in mountainous terrain. But for 90% general everyday driving, it is much too aggressive for my taste. Downshifts on mild braking revving the engine to 4000 RPM. Extra brake related shifting and generally higher revs. I find it most useful on extended downgrades to minimize braking.
FWIW Lazy Daze also recommends Tow Haul only as needed. It's just an opinion, but it does mirror my own.
My opinion might be different if I was towing or had a bigger/heavier class C,