No complaints whatsoever yet - though I've not taxed it up long inclines, the short inclines, even steep ones, are no trouble... high RPMs (3000-ish) but smooth. I do have a Fastway e2 WDH with built-in Sway control and Brake Controller. BTW - I was warned NOT to get the 8000/800 lb hitch because some Lawyer will infer you had it set up outside Nissan Specs... It has some aerodynamics to it at the front, and I can feel the truck blast but never once felt it sway. While I know I am at Max, I am confident in its performance so far... and I am told the '18 CVT does not have the failure issues with earlier models... even so, I did change the CVT fluid and plan to do it fairly often, even at $220 each time.You're right at the max and it's safely worked for you and your specific usage. That's all that matters. I think this is great information and even better than you shared it with us. This is one of the few reports we've had with someone at the max and having no major complaints.
Big box shape travel trailers are the worst case scenario for any tow rig. Totally different animal than towing a boat, popup camper, flatbed trailer, etc.