5er vs Winnebago

No previous RV experience? No problem with that, except when you ask for advice for a major question of this vs that. Everyone is different. You may own a large pick up today and find 5th wheels the way to go. You may not and find the simplicity and nice ride of a large Class A diesel pusher more your style. Or...you try both and find RVing is not for you.

Just pick the easiest option for your current status and situation...and go from there.

You might consider renting a Class A to see what you think of it and are comfortable driving it.

If you're going to be stationary for long periods, I would go with a 5er.
If you will change locations often, I would chose a Class A or C.
I think the set up/tear down on the A or C is quicker and easier.
The 5er has more space.
YOU must decide what is best for you.

Don't be in a hurry and ask lots of questions, someone will have an answer.
Take your time and enjoy the search. :)

Our intent is to travel weeks to months at a time. The RVs we have viewed are newer models 2014, 2015 and 2016s. If we decide on the 5er, we plan to also purchase a 2500 Silverado Duramax.

New models or older?

And do you already have a vehicle suitable to tow the 5Ws you mentioned?

Welcome to the forum.
Have you closely looked at the RV's you are considering?
Which floor plan works best for you?
That's a good place to start.

Do you have a truck capable of pulling a 5th wheel?
How will you use the RV? Stay in one location for weeks or longer?
Go to a new location every week?
How you plan to use it can make a difference in your choice.