I've had an Itasca Navion 24G since 2015. Very few problems. Here in San Diego there are choices in where to get it serviced - I've used Sprinter Pitstop, MB of San Diego, and Pacific Automotive (not a specialty shop but they are fine for routine maintnence items - oil changes, etc.). There have been some recalls, none of them urgent but waiting for the propane hose one restricted use of the propane systems for a few weeks while I waited for La Mesa RV to get the parts (I only used La Mesa this one time, had no choice as it was on the Winnebago warranty, as far as I can tell they did the recall as well as anyone else would have).
Since my previous RV was a truck camper the Navion felt much roomier in comparison. Coming from a Class A you'll experience the opposite feeling.
Storage space seems adequate to me - I carry some chairs, tools, barbecue, propane campfire, dutch ovens etc. I did a lot of long distance motorcycle and bicycle touring in previous decades so have learned to pack light - your mileage may vary.
Speaking of mileage I get around 15 mpg without towing, around 13 mpg towing a Jeep Wrangler (3800 pounds).
The overall ownership/use experience has been quite positive so far - 6 years, 60k miles.
And one last point that was important to me the Sprinter has much more legroom than the Ford chassis Class C's - at 6' 4" this matters to me.