The PFE232 isolate more than FX700 because it sit deeper in the ear and FX700 made for to stay in outer like UE TF10Pro and both has bigger nozels and FX700 still isolate pretty good(more than average inearbuds). If you want more natural wood (slightly) warm tune to the music then FX700 are pretty good( they offers extended highs, deep reverbing bass and detailed mids) and if need to change the sound often and more on detailed side then PFE232 are superb sounding IEMs.
Do you think I could improve the PFE232's isol;ation by switching tips? Perhaps there is one tip that isolates well enough for planes? Seriously, these are THE iem's for me.