I don't use RemOil and for electronic/electrical applications it depends on the application - for minor cleaning like for connections I mostly use Deoxit. Protection (non-conductive), maybe Corrosion X, liquid tape... depends what I'm doing.
Since I don't use RemOil for anything, I don't know how it compares to WD40.
A far as gun oils go, lately I been using Slip 2000 EWL and Weapons Shield.