Well yes, the PS4 is a beast, don't forget that it is entering its sixth year unlike the switch which is very young. So the most surprising of the two is the performance of the PS4.
I'd say they are equally as impressive. One, Nintendo was able to turn things around in such a massive way going from Wii U -> Switch. Next, although the PS4 numbers are fantastic for a device of its age, the Switch numbers are ridiculous no matter how young (and many devices of that age saw nowhere near that amount)!
So, while I get that one is doing surprisingly well, to me, they are equally impressive feats.