PB Blaster here....works if directions are followed. I have a regime that I use on OLD motorcycle bolts that requires a squirt a day for a week. Sounds excessive but it works and I rarely have to drill out an old busted bolt or screw.
PB for penetrating/loosening. WD40 for cleaning rust off of things, with steel wool. Also Boeshield, but harder to come by sometimes, with my various hours, hence the wd40.
If I can find it I still love Liquid Wrench in the blue can. Last time I bought some stuff in the yellow can and it sprays out more like foam. Don't care for it.