It obviously isn't for everyone, but we're setting it up in a way that'll work for a bunch of 'moderate' fliers.
1- Our group is about 1/2 and 1/2. I'll be doing most of my flying during the week, others will be weekends, and we'll split on other time frames. We obviously cannot fly ALL weekend every weekend, but we expect availability to be high.
2- The whole group has jobs, so going to airshows would take a bit of planning for everyone. We still plan on being able to divy them up fairly easily though, since our group doesn't have much interest in going.
3- That is what insurance is for
The sour feelings are avoided by just joining in with a good group of people.
4- We are using a hangar, so the driving is a necessity I guess, but we decided early that everyone would split mistake costs. It saves the headache of arguments and has been a pretty easy decision so far.
Ego issues are the biggest deal which can be solved by choosing the right partners. I know the partnership isn't for everyone, but if you are an moderate-use pilot, the share works fantastically. In our case we all get a plane that gets constructed in roughly 6-7 months with good build quality (Dick has complemented us on the work), and significantly reduced costs.
I think the increased build quality comes from having someone watching over your shoulder all the time, as well as someone to ask if you aren't sure how to do something. Additionally, we've avoided the standard 'burn out' problems that many builders have by having them offset enough that work never seems to slow
Definitely something that should be considered by someone considering a build.