I'll find the detailed post later but stacking crit or spell speed is really a preference. Stacking one over the other you are actually going to gimp yourself because the max crit rate we can get on our gear is around 15% I believe. (I'll find post later). Personally you should get myth pants first because they drop from Turn 5 coil. Everything else you shouldn't really need myth pieces. All your other gear drops from coil 1-4 and I think its a waste of time. I spend my myth on my monk sub class. With two healers in full darklight and +1s we had no problem healing turn 1-4 with ease. I saw no reason to spend myth prices if I can do all content without it. Only piece might be another ring. But again...not needed for any current or future content (at least in next 4-5 months)