Funny thing... I have a nice Curt WDH... and it's still in the box.
I've towed quite a few hundred miles this year so far w/o it, and I do perfectly fine. I keep it around in case I find I'll be driving through a state where one is required.
I should however say why...
1) I only tow 4,000 lbs of RV trailer. The trailer is 22' long and 7.5' wide. It has nice and big A/T tires on a single axle. I don't tow anything bigger.
2) I've done up to 70mph on the freeways (I-5) and 65mph on mountain roads (throughout the Pacific NW) with no incident, or even any odd feelings on the wheel.
3) I am religious about proper weight and balance when it comes to loading the trailer.
4) Payload capacity is 1700 lbs, but I don't come anywhere near eating that up (tongue weight of 400lbs, the weight of the missus, maybe 100 lbs of firewood in the bed and 250 lbs of assorted chocks, spare propane cans and sundry...)
I may put it on, but I just haven't been arsed enough to bother just yet.
Not seeing where I'd be wrong in not bothering, but I'm more than willing to entertain any theories as to why I would be.