It's not the delay as you described, it's that sometimes you click once and it moves 2-3 degrees, sometimes you click once and it moves 20-30 degrees, so unpredictable, not slow and that's what I meant by twitchy is you can go back and forth and not get what you want, but drawing a box around the suspect zooms in on that location and that's a better way to handle that camera. I would think they would fix this with a firmware update, hopefully they read my review.
You have to realize, this camera, first shown at ISC West back in mid-April and wasn't even available back then, is fairly new. When I reviewed the Axis Q60 it had been out for several months and it was still buggy to the point I was not even going to do the review and spent a month with their engineers trying to fix basic issues.
In contrast, the ACTi PTZ functionality is amazing. It's the only camera I've seen that can PTZ all at once, where the Hikvision and Dahua's I've used do each function serially. But there's no IR, so depends on needs.
As for this Dahua vs. the all white one, my customer has replaced all of those for this one and has re-ordered, so he must like them, mostly because of the -15 degree tilt.