Another fan of Obenauf's LP here. Back in the day it was just mink oil, but that's before I really researched anything or had boots that I cared much about.
Obenaufs is oil based and may damage the glue that holds on rubber rands. Water based like nikwax is better on your boots but not as effective and wears off faster than obenaufs so pick your poison. I am going to give reviveX a try next.
Obenauf's is really good but I use nikwax or grangers wax paste on my lowas because on one pair the rand started separating from the Obenauf's. Also, IMO with the gortex, windtex, or event membranes you really only need to keep the leather from drying out and cracking or absorbing too much water.