I used to be a complete
GW Black rattlecan addict. I'd use it to prime anything. The White, I had trouble with powdery finishes but the Black went on smooth.
Now, however, I have gone Vallejo all the way. I bought black, grey, and white and a cheap suction feed external mix spraygun for about £16. I now start at the bottom of my models and spray upwards with the black, change to the grey - generally with a few drops of the black in as my bottle of grey seems rather light - and spray that whilst the black is still wet from the side so that the grey colout fades into the black around the knees of the figure. Then I add a thin coat of white (NOT a coat of thinned white) sprayed downwards to cover the head and shoulders.
Keeping my base colours thin enough, the effect of the different colours of primer show through and I get the effect of slightly more light at the top of the model than at the bottom.
This shows what I mean.