I agree with Stan. I just got a batch of CPM154 (very similar to ATS-34) blades back from HT, and I wish I'd taken them to a higher finish beforehand. They had no hard scale or pitting on them, just the oxide color from the high heat/deep cold, which sands off easily. Next batch, I'll hand-sand to a higher grit before HT and save me some time later.
In any case, ATS-34 and CPM154 both share a very good reputation for knives. I didn't find the 154 terribly difficult to grind, but it sure does take a while to get coarse scratches out after HT. Once you get up to a smooth 400-grit finish it polishes up pretty quickly.