Can the community recommend some manufacturers with better than average or high quality?
Quality covers many aspects, e.g. build construction, design features, components selection, etc. The more expensive models are always better overall, yet may still have production defects or design mistakes in any given model or year.
Most of the manufacturers build an array of models at different price points, so there are Chevies and Cadillacs in each product line. Some of the difference is amenities, but the rest is either under-the-covers differences or the materials and components used. Basically there are entry-level models, mid-range models, and luxury models. Entry level sacrifices bits and pieces all over to achieve a lower price point. Mid-level buys some of that back, and the high (luxury) end adds both amenities and superior construction attributes.
You didn't mention new vs used. We mostly recommend buying used, especially for newcomers. It's a house, not a car, so condition and livability are the key criteria, not age or miles. Model year Age however, complicates the recommendations because the RV industry went through a major shale-out with the 2008 economic collapse. Five major RV makers went belly-up and their brand names have either disappeared or been reincarnated as radically different rigs. Tiffin, Winnebago, and Newmar are the major survivors.
Tiffin has made a reputation building good value in their mid and top end models since around 2006. Newmar is another brand that consistently gets good reports, as does Winnebago. That doesn't make any of them trouble-free, though.
You need to look at a lot of RV models and floor plans to get a feel for what size and layout suits you. And apply a budget to it, since price range is broad. Then we can reasonably discuss good-better-best in that type and price range.