To be honest from your description of what you would like to have from your RAGBRAI experience you sound like PBV people to me! I know they are “expensive” but that is a fair price for the level of service they provide. I hear good reports on Bubbas and Brancel too and I can’t recall hearing anything bad about the others on your list so I think that any of the ones you are considering are worth considering. I think Brancel and Bubbas are both in the same league as PBV price and service wise, I don’t know about the other two.
The one time I did this ride with a charter was last year and I used the Riverbend Club/Charter. They are on the opposite end of the spectrum from your list: very affordable and I don’t think they were much over 100 riders, if that, and that was not a problem at all. I was 100% satisfied with their efforts on my behalf and they did everything I wanted them to do but what I wanted was a lot less that what you want! I had to bring and setup/teardown my own tent for example and rather than finding that to be a chore it became a comforting part of the rhythm of life for the week. Showers were never hard to find and they were nice hot showers. Some in schools, YMCAs, aquatic centers, some in commercial shower trucks.
In other words, if you were to choose to go with one of the least expensive charters because some in your group need to save money you will certainly have a different sort of experience from being pampered by PBV and the like but you will find it to be a grand experience all the same. And here’s a hint: that “free” beer PBV gave you?, yeah, you paid for that! There’s no free beer on RAGBRAI but there are many fine beers to be had beyond the ones that PBV chooses for you, not that PBV’s choices are bad.
Talk it over with your group and make the decision that fits everyone’s budget and expectations. RAGBRAI is going to be great no matter how you do it!