Originally Posted by
UnbeatenPath
I would say 135 prepares you better for the 121 world. I did both, and yes teaching makes you a good pilot, but being IFR all the time in bad weather going to major airports with complex procedures teaches you more for 121. Also, ground school, sims, and checkride all are very similar to 121
That^^
To max the chance of your app getting pulled, do both. CFI until you have the hours for a year at a 135 outfit. Preferably NOT SIC at the 135 outfit.