First of all, look at a lot of class A motorhomes from other manufacturers. If it is your first class A motorhome, I strongly suggest buying a used unit and looking for one of the higher quality models. We searched for our first class A about a year ago or more, and we were looking at used motorhomes due to a tight budget. We ended up narrowing our search down to Tiffin, Newmar and Winnebago based upon reviews and what we saw in our search. When it comes to Winnebago, I'd buy one of their better motorhomes used as it will have more features and be trimmed out a lot nicer. Most reviewers consider the Newmar and Tiffin units to be better. I found Randall Eaton's "Motorhome Comparison Guide" to be very informative and useful for a first time buyer. It' a little pricey but worth it.
Don't get me wrong....I like "new" and our two travel trailers were purchased new. But we've been very happy with our used Newmar and the longer I have it, the more I can see the quality of it compared to entry level units from other companies. But, we could have been just as happy with a comparable unit from Tiffin or Winnebago.
It's true that just about all of the gas motorhomes are on the Ford F53 chassis, but there are a lot of differences in the components used and construction techniques used to build the "house". So, take your time and try to avoid the allure of the surface glitz and figure out what size and floor plan will work for you. I suggest reading this article on wheelbase ratio:
https://axleaddict.com/rvs/Why-RV-Wheel-Base-Ratio-Is-Important
Good luck in your search and I hope you find a winner!