We have had our 2012 Nexus Phantom 23P (24'), Class C for nearly 2 years and 23,000 miles. I have experienced Zero, Zip, Nada handling/ride issues. It is always smooth and steady and passing trucks are no problem. Yes, I feel their bow wave but so do other trucks. Driving in anything up to 35 mph winds is easy one handed steering (over 35 I just get off the road). Keep in mind that this is probably the largest (tallest - 11'4", widest - 101"), 24' C on the road today).

Our 2011 chassis has GVWR of 11,500# (Ford increased the E-350 to 12,500# with the 2012 chassis), and we travel fully loaded at around 11,000# (as we keep adding "stuff" and I carry lots of tools and toys). :S
Some day I will replace the original shocks, probably in another 20,000 miles or so and Bilsteins are at the top of my shopping list. I run Michelin LTX M/S 2's at 60 psi on the front and 65 on the rears. This gives me about a 20 - 25% cushion over and above the weights they are carrying/rated for and as noted the handling and ride are both excellent.
Watch the ccc/occc ratings for any rig you are contemplating as some are woefully short on payload and will be subject to overloading. Anything on a Mercedes Sprinter chassis will be suspect. Our Nexus has 3,363# of payload and yes, we use most of it (without any problems).
IMHO: Any new motorhome that has handling issues off the showroom floor is the wrong coach, period. Properly loaded and with the right tires/psi a new coach should perform flawlessly without any additional (costly), modifications.
As always.... Opinions and YMMV.
:C
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