I'm not a oil person but I do use preshave creams,mostly Proraso PrePost,I use that just about everyday,or Feather Preshave.I just ordered TSD ISZ Preshave can't wait to try that
Since upgrading my soaps and blades, and face lathering more, I do find I use pre-shave oil much less. Prior, when I was using lesser soaps, blades, and technique, it was extremely helpful to my neck. Currently I use it mostly in the winter to offset dry skin effects.
I just stumbled upon this thread. Never used oil yet. I'll try tomorrow (if I don't forget - which I do a lot!)
As far as pre-oil go I only used it for the first time a few shaves ago as extra prep for my first go with a shavette. There were to many varibles in that shave to tell if it made a diffrence. My normal routine is the same as Mitch with porasso pre in place of oil and an extra step of pre under the lather. When using oil I replace the porasso with oil. The effects seems similar , the oil a little less vicus and sticks around longer so generialy only a 1st and 3rd pass application are needed not all 3 like the pre balm I use. Further tests on this method will be taken on my shaving journy .
I face lather and find the pre-shave oils I have tried to substantially reduce the quality of the lather I can build, especially for soaps. I did not like them at all, but others swear by them.