Flip a coin, and get the floor plan you like. Learn how to use a screw driver and pliers. Read a few web sites on RV maintenance and watch lots of YouTube videos how do to everything on an RV and you'll probably be OK then.
You really won't know how good or bad a dealership is with after purchase follow-up until you actually experience it. But check the Better Business Bureau for complaints.
But, on thing you also REALLY need to consider about popular RV models is this: The more popular a model the more sales there well be. The more sales, the more failures too! Larger failures means MORE people are hitting the social media circuit which makes the bigger more popular RV more noticeable. Just because you hear rumblings of negativity so much, does not mean it's all that way. It just means there are more purchased and more who will grumble about problems.
A manufacturer sell 1000 RV's Of those 1000 RV's 50 of them are sold and have problems. 50 people now post on social media their problems. The other 950 who are happy never post anything.
Another manufacturer, much smaller, sells only 100 RV's. Of those 100, 5 are sold with problems. Now, only 5 people post negative responses on social media. The percentage for both manufacturers is still 5% of failure, but who do you think get's more attention! Right! The company that has more negative feedback, only because of shear volume.
Another thing you REALLY need to considering when hearing about negative experiences with RV's is the very nature of the person themselves who are making the complaints. Some folks purchase an RV with the mentality they are built like tanks and treat them like they are going to war. The get beat up very quick and fast and things break. Is this the fault of the RV manufacturer? No! It's the fault of the owner. The camper was never intended to be used like a battlefield tank. And if you examine closely, a lot of folks who complain about inferior quality of an RV purchase them with wrong expectations and end up damaging something, then call "foul" at the manufacturer. You can't sit a 1000 pound person on a child's high chair and expect the high chair to survive! Yet, folks expect RV's to survive their abuse. These are the ones who complain on Social Media. (Not all, but read carefully and you'll see what I mean).
You are doing the right thing and it sounds like you are doing your research so you won't be blind sided. The success to any RV ownership is to understand the intention for which the RV was built, they type of camping it was built for, how well the owner fixes small problems before they become big ones, and how well the owner does simple daily maintenance. Abuse them, and they don't last. It's that simple.
After all that... well ... I recommend a Keystone Outback. Mine has been pretty much trouble free, except for the stuff I've fumbled up myself.