I may need to eat a little crow here... I got my hands on a 120hv to compare with the issue you describe. My other geckos are 65, 85, 125, 155, and 150HV, and they all worked fine. I ran the 120HV on the bench the other day, (no prop) and I could kinda see a little hesitation on spool up. Hoping to get some flight time this weekend so I can say definitively if there is an issue for me.
Hard to say if what I saw on the bench was accurate or not, since there wasn't a prop on. I'll report back with my findings and opinion.