If I were competing, it might be worth the extra $2 a box for more consistent ammo.
If I ever saw any difference in my score that could be attributed to the ammo, I'd agree.
But seriously, I've shot STS, AA, and my own handloads with various components including an IMO "best-of" mix of STS and AA components. I'm still set up to reload, but until I get something like STS shot for under $25 a bag again, it just doesn't make sense to me, to spend the time.
YMMV