My Sinn 105 is not particularly accurate, and every few days I adjust it. I asked YVK about his Sinn 856, and he wasn't sure about accuracy. I asked if he was wearing his, and as he was, what time it said. He was ten or twelve minutes fast, but didn't remember the last time he adjusted it. My Mido was spot on time wise, but my day/date were off due to user error.
I mostly use my Casio ProTek solar atomic to set time on my other watches.