The event has been in existence for many years at different locations in the Ypsilanti/Ann Arbor area. I haven't attended in years, but when I did attend, I'd rate it fair to good. As with all of them, it depends on what you are looking for.
Every now and then they used to schedule it after a EFV-8C National Meet in Dearborn. I have been to it about 4 times now, because of that scheduling and I live in Minnesota.
Have always found some good stuff -- but there was always items there that I wasn't looking for.
Haven't been to it since 2018, so can't give a recent assessment.