I've shot both for years. Mostly Doug Fir, by choice. I find fir holds up better stumping. To my eye, they fly slightly different; fir seems to recover faster, and spruce fly a little flatter.
I'm pulling around 43lbs, and I always ask around for the lightest weight set of shafts in order to keep my gpp at 10-10.5; with spruce it's easier (maybe not now with Hildebrand not taking orders).
Only tried one set of tail tapered shafts, and I couldn't notice a flight or performance difference, though I know some folks do.
Can't go wrong wih surewoods, or Wapiti, for fir.