Steve, I recommend watching "project farm" channel on YouTube, he does a pretty comprehensive comparison of all the penetration oils head to head and has two videos regarding this subject... you'll be surprised of the results cause we old timers keep thinking Kroil is best... which as it seems with today's technology that it's not as we claim it to be...
I like this guy and is videos and I hate youtube videos....but I can't say I have seen anything near these results.
I have never seen liquid wrench work as well as PB blaster and there is no way wd40 is even close to as good as PB and no way better.
I've been using all three for over 40 years. I just haven't seen similar results.