Per my experience the biggest problem with pickup stabilization is tire flex....

 

The deeper gearing is a huge benefit you're missing out on not getting the dually, probably the single most important differnce inside the current 350 lineup.

 

M Frank not to get you mad but I don't see a truck with SRW towing as well as a truck with DRW no matter what the suspension is built like. I think that salesman is full of B.S. I have a dually and have towed my toy hauler in 50 mph winds and was able to keep the truck and trailer straight as an arrow down the highway. I believe that if my truck was a SRW I would have had trouble in that wind.

 

The salesman must be referring to the new "Trailer Sway" control feature on the 2011 Super Duties. In the video, the trailer is NOT a 5th wheel trailer NOR is it 40' in length.

2011 Ford Super Duty - Trailer Sway - YouTube

 

A dually will definately give you a better ride

 

Watching the above video the "Trailer sway" is just additional software to ESP program.
My 99 Ford doesn't have ESP, while my 98 Mercedes does. Those programs can help you in recovering from deep trouble, but will not help you in protecting from going into them.
It is like band aid and steel mesh gloves used by the butchers. The first one will patch the wound, while the second one will prevent the wound to happen.
Dually will not give you better ride when empty. I drive with 90 psi in my tires and when empty have hard time to control my flatbed on any road crown. Sure releasing the pressure would make big difference, but who wants to play with it?

 

My salesman told me that break-in was not necessary, and he was the fleet sales manager, but the manual that came with the ford truck states how to perform break-in. Now the salesman would not stretch the truth.... According to my trailer manufacturer I can haul it with a 250 (unless I happen to load it), I got a 350 then a year later got lucky and got 1k less than I paid for my srw and moved to a drw.
Look at your driving area and your towing requirements then look at the printed specs from Ford, make a educated decision.
Note: drw is a lot worse in snow. I have to get 500 lbs of ballast before winter.

 

I have a 34 foot 5th wheel and have made multiple cross-country trips. This has been done in a variety of weather including high winds. I prefer the stabilization of having 4 wheels in the back, which allows me to enjoy the drive more. Good luck!

Too bad you can't test drive both hooked to your 5th wheel and then make your decision.

 

One of the benefits of the dually is that it FEELS more stable than the srw. Some people might blow that off but when you feel more comfortable , everything is easier. Unless you do a lot of offroading, or parking on city streets, drw is probably a better choice.

I can't recall hearing anyone on here talk about doing a lot of towing and wish they had the srw instead of the drw.

 

My thoughts exactly. I towed with both, and the extra cost of two tires, and parking issues are far less of a concerne to me than the piece of mind I have while towing with a drw truck.
Its a no brainer for me even if I only towed 10% of the time.
my .02

 

Buy the dually. Passed my anti sway system to my buddy for his F250. I bought the dually for the following reason:
Friend of mine blew a rear tire towing a trailer at 70MPH. Truck and trailer tried to swap ends. He saved it but needed to change shorts.
I figure even if I blow a rear tire and tear off the fender so what. That's why I buy insurance to fix the fender well and dually flair. Can't do that when it swaps ends and kills me. Mountain driving is very unforgiving at 65-70 MPH with a blown rear tire.

 

I once had a left rear tire on my E-350 go flat (Catastrophic valve stem failure) while towing a 30' receiver pull travel trailer at 65mph.
The incident had me thinking about converting my van into a dually.
Ford dual wheel conversion kits with wheels