Originally Posted by kevdiv48
I wouldn't go as far as saying that, but there is definitely a lot left to be desired.
For instance, for their ratings there is little differentiation between discs that are high speed understable but low speed stable (i.e. -1, 3)and discs that are high speed stable and low speed stable (i.e. 0, 2). Under their system teebirds and eagles would be rated the same, but if thrown at the ideal speed they clearly have different flight paths. And would a beast, katana, valkyrie or any other disc that has equal turn and fade be rated as a 0? If they were it would be very deceiving to someone that thought they flew straight as opposed to on an S curve line.
I would, and you pointed out exactly why. The flight rating doesn't tell you anything about how the disc flies (glidey v. non-glidey) or how it gets there (turn/fade or resistance to the same) or how hard/fast you need it to fly (speed) (although their flight chart does show this slightly, but then only in distance potential, not speed), it just tells you net stability.
Thus, their stability ratings tell you nothing you need to know at worst and mislead at best.