I wish I could make a bolder prediction for Switch, but it's still very early. It could end up anywhere for all I know, including S-SS. But at the very least, it should make 20-25m at this rate.
However, a year from now I should be able to make a much bolder prediction.
As for PS4, I expect around 110-115M at the moment.
If you put a gun to my head and force me to chose now, I'd say PS4 by a huge margin is the safer bet, simply because it has already performed well for multiple years. Which is the challenge.