I'm with everyone else - stunned at how awesome Arcadia is. Great flow and well-constructed slopes in both directions - modern sustainable trail techniques are so much more effective (and fun to ride) than old erosion-prone straight up-and-down the hill trails.
Having ridden mostly on MMBA trails with the exception of general unmarked trails in Sweden, I was a bit confused about the lack of directional markings - but I see now. We rode it clockwise; we'll have to try it the other way next time. The only part I can see being a bit of a downer going counterclockwise is how the long downhill through the meadow two and a half miles in when going clockwise turns into a long uphill in the sun.
With a trail that good it's hard to believe there weren't more people riding there... Before we left from the trailhead half a dozen other riders finished together and left, and there weren't any other riders the entire hour and ten minutes it took us to finish the loop (including a few water breaks). That was early Saturday afternoon!
And yes, there was glass in the parking lot, but no break-ins while we were there. I hope they catch the thieves...
Just for the record, the map "Powered by Google" in the trail guide shows the trailhead at wrong end of St. Pierre Road - the trail map has it right, but it ought to be fixed so that no one gets confused.