From a concert's set list to the number of musicians on stage to mike setups to the selection of instruments, DSO's adherence to authenticity is solid. The only mystery is the historical concert selected; DSO never reveals this information until right before the first encore. Once date and location are confessed, DSO then breaks into a small selection of tunes chosen by the group itself -- a small reward perhaps for DSO's loyalty to the past.
Dark Star Orchestra obviously does its homework before going on stage, and better yet, the band has the chops to pull off its reclamation project. Of course, the subtler points will be lost on most listeners, save for those Dead freaks who can tell you how long Jerry Garcia's solo was on "Friend of the Devil" at Golden Gate Park in 1975. Still, DSO fans expend a lot of energy trying to determine which show is being re-created, whether L.A. '77, Cornell University '82, Soldier Field '91 or some other date plucked from history. It gets so competitive that DSO asks fans not to bet on the outcome.
Your tolerance for this kind of thing probably depends on your tolerance in general for obsessive nostalgia. But even if you're not inclined toward living in the past, chances are this could be fun for those who simply like to party to improvised jam rock. Curiosity seekers may also enjoy themselves, and perhaps even discover what the whole Dead thing was about.