Richard,
My vote is for # 3 at NGLA.
In your presentation you seem to focus on the unique bunker at Prestwick.
At NGLA, the tee shot is exciting and requires a choice, a plan for attacking the hole.
The diagonal bunker off the tee, coupled with the tall fescue ascending the hill fronting the DZ put a premium on the drive and your choice in terms of the line of play AND distance.
Once safely in the DZ, your second shot is influenced by your lie.
Uphill, downhilll or sidehill.
The second shot also tends to be longer.
And, the second shot requires far more trajectory.
I also think the green on # 3 is far more complex, it's one of those greens within a green as you have the far right upper plateau, the lower left bowl, the back upper tier and the contours connecting these areas.
The bunkering is also diverse, with the deep right side bunker flanking the green and the bunkers fronting and offset from the green.
Both holes are wonderful holes, and I would ask responders to think of the question of preference in the context of repeat play.
Which hole would you prefer to play on a daily basis.
For me, it's # 3 at NGLA by quite a margin