I never expect penetrating oil to do any good, and therefore I'm never disappointed. I like the advertising for B'Laster. It dissolves a styrofoam cup. But none of the crap I work on is seized-up with styrofoam. I've seen with my own eyes, guys spraying penetrating oil on seized crap that's sealed with air-tight gaskets, or electro-corroded due to dissimilar metals getting too friendly in blind holes. The penetrant cannot get to what's seized. Makes a nice, stinky puddle on the ground, though.
OTOH, I've never seen penetrating oil make things worse. So I use whatever's on sale, or whatever is in the most-colorful can when I'm shopping. B'Laster, Liquid Wrench, Deep Creep, Store brand, the latest purchase is WD-40 "Specialist". I marinade when I can.
When I run into trouble with seized bolts, I really prefer to break out Mr. Oxy-Acetylene torch. God bless the glowing-orange rust-buster.
I would like to try the portable "inductive heaters" for making bolts glow. But I'm wary of sinking hundreds of dollars into equipment that look like consumer-grade sillytools.