It really depends on mostly two things:
A)If the Switch version is not considerably inferior to the other versions.
B)Perceived value.As long as the Switch version is not more expensive than the others or/and if the portability factor for one particular game makes it more desirable than the others.
All in all, Ill be buying the version that ends up being more convenient to me.So my answer is both version, whatever I think its best.
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1