I like (+) (-) (GND) , not GND in the middle.
A lot of chinese supplies seem to have PE GND in the middle like that. It means you can't use a dual banana jack to BNC, which I like sometimes, and with a BNC to grabbers at the other end. They often show pictures that have PE GND strapped to the (-) of the PSU, so I think that's why they do it that way. HP has a few older PSUs with PE GND in the middle too, so they are guilty as well. There is no standard, although many people have a preference, one way or another.
I much prefer the older triangle arrangement, with PE GND above and centered between the (+) (-) , or at least at a right angle, with (+) (-) side by side at 3/4" spacing, and the PE GND above or below the (-) jack, again at 3/4" spacing.
Agilent's current models seem to have it in a good arrangement and with proper spacing.