i have a mate who's doing 2-3 di2 installs a week and at least one of the new V2 eps installs a week..
set up wise while a little more involved he says eps is really easy to set up and once its locked in its very very good... hardest thing is lining every thing up for the battery down the tube but once you've done it once.... it isn't very hard..
any frame built for older eps or di2 is going to have an exit for the external battery mount ( perfect place for you charger port duhh!! ) or you could take my solution and get a custom berk combo thats got the port in the post under the saddle.. normal persons who use normal seat posts could have the cable exit in the post through the post cradle.
ive installed di2, and repaired busted wringing looms trouble shot overly tight limit screws and it is nice and straight forward..
but i will not adorn my own bikes with gear made by a company thats make the lion share of their profits from fishing gear.. and while it works really bloody well its not good enough for me
i think they both work on equal terms with each other with the campy been a little heavier than the shimano offering, campag have nicer ergonomics and a better rear mech, shimano having lighter and better front mech and battery, campag still wining in the looks and prestige stakes ( every ome bike and its dog have di or ui2 these days )