We bought a used 2006 B Sprinter, LTV like Asheguy's, and had numerous wonderful road trips in it, most lasting from 30 to 60 days, around the US and Canada, both summer and winter. It was just the two of us, unforgettable adventures.
The mileage was excellent, about 23-25 mpg (diesel) and we had minimal repairs, all easily handled without a Mercedes dealer. You just can't beat the nimble lifestyle and easy driving of a B. I loved how fast we could set up and depart, and the tight spaces we could navigate.
It's liberating to travel light, and just grocery shop or do laundry once a week or so. We used CG showers most of the time, and prepared almost all our meals - we eat out once a week at most. I worried about the size of the tanks but that concern evaporated in actual use. We had a propane generator. Our refrigerator was a 3-way which I liked...used 12-volt while driving, propane when parked without hookups and out exploring, and 120 while attached to shore power.
We traded for a small C because a large Labrador Retriever became part of our lives, along with her food, toys, meds, bowls, towels, shed fur, and sleeping accommodations. We needed a little more "living room" space where she can sprawl and sleep on her bed, without our having to climb over her. I must admit I'm also happy to have a bigger bathroom with shower stall and a larger refrigerator (still 3-way.)
If you are an organized, "place for everything" type person, and get along easily with your travel companion, it's a plus in a B, but that's probably the case in any RV.