We came across this information awhile back, if you do your own repairs you may be interested in this.....
Penetrating Oils Compared
Machinist's Workshop magazine actually tested penetrates for break
out torque on rusted nuts. Significant results! They arranged a
subjective test of all the popular penetrates with the control being the torque
required to remove the nut from a "scientifically rusted" environment. Results
relative to 'naturally rusted' conditions considered equivalent in standing.
Penetrating oil ........... Average load
None ..................... 516 pounds
WD-40 .................... 238 pounds
PB Blaster ............... 214 pounds
Liquid Wrench ............. 127 pounds
Kano Kroil ............... 106 pounds
ATF-Acetone mix............ 53 pounds
The Automatic Transmission fluid (ATF)-Acetone mix was a "home brew"
mix of 50 - 50 automatic transmission fluid and acetone.
Note the "home brew" was better than any commercial product in this
one particular test. A local machinist group mixed up a batch and
all now use it with equally good results. Note also that "Liquid
Wrench" is about as good as "Kroil" for about 20% of the price
I plan on mixing up some of the home brew after I use up my PB Blaster which I had always thought was the best of the lot....

....its seems according to the test that liquid wrench which I had used for years had almost 100 lbs. difference from the newer products..