Silicon oil is silicon oil... to a point. Not one of the off the shelf companies manufactures their own (to my knowledge), they will buy it in from oil companies.
The only thing which can potentially make one better than the other is it's rated weight vs. the measured weight - if your bottle of say, 500cst is actually measuring out at 580cst on one brand, whereas it may measure 495 on another.
All said and done, if it works for you then there's no reason to change.
