For me I have three that I use for most penetrating needs. Kroil, PB Blaster and Thrust with all being almost identical in performance so I mostly use PB because it's available everywhere...
The rest of them I've tried couldn't penetrate a condom with a razor blade & WD-40 is a joke unless you want to clean lipstick off a counter top..
Please be very careful with REAL penetrating fluids. PB Blaster can ruin engine seals
output shaft seals
. Ask me how I know... Doh!
I have not tried VpCI SuperPenetrant but am always weary & a bit skeptical when a company puts out their own, self published, white paper claiming superiority.
Having grown up working on boats and antique cars I know how Thrust, PB and Kroil work and they work very well, I also know, from experience & use, that WD does about as much as using water
and Liquid Wrench is not far behind..