Just got mine set up yeasterday, there's a little play between the chainrings and the spider, but not in the way that it actually matters. The provided spider mount tool didn't quite fit my bb tool, so i had to cover it with a cloth and grab it with pliers to get the leverage to tighten the mount.
Power numbers seen pretty much dead on with my direto xr after using just auto zero. Chainrings seem to shift well so far.