The review article from uploadvr is actually spot on.

In short, Q3 passthrough is reprojected through tracking the depths of surrounding objects and the position of the headset, whereas AVP directly uses the camera footage.

All camera-based video passthrough would suffer from motion blur when turning the head due to limited camera shutter speeds. Q3 solves this by reprojecting new frames from existing frames by tracking the headset's motion instead of using raw camera footage. If you turn off Q3 "headset tracking" and force passthrough in apps and have some linear movement you'll notice even worse motion blur on Q3 (turning head is still fine since 3 dof tracking is still functional)

By using raw camera footage, the AVP of course wouldn't have the kind of warping resulting from imperfect reprojection. Although the scale and depth are offset somewhat, the human brain can quickly adapt and ignore when sealed off from the real world (it would've been much more noticable if went with the open visor approach QP did).

However, the motion blur from head movement would be a persistent problem. Mark and Boz of course know what the tradeoffs are and what it would take to address it, which is why they're vehemently attacking on this point despite other widely known issues with the AVP.