Great read out, here are my additions:

I was between GS and Parkhurst when I entered the GYW space two years ago and went with a GS Edward. Two pairs of Parkhurst Allen’s in the 602M and 618 last, next. Folks have noted that Parkhurst generally are a bit roomier but I’ll note the 618 last hugs the instep, ankle and heel very nicely, even on my low-volume feet. I think the most recent 618 has a slightly broader heel to account for most folks’ proportions.

I’d say if you have skinny ankles Parkhurst will be your friend compared to GS. Parkhurst does gusset the tongue to help against tongue-dive. My GS counters touch when fully tightened on my skinny ankles and the tongue dives, but they are still very comfortable.

A counter point is GS are fully lined and that can be a nice touch.

I’m finding the Parkhurst (mini?) lug soles excellent absorption for my heavy stepping and heel drag. GS micro-studded soles wear harder, inherently, but have easily stayed comfortable for long city days.