both the exam are interlinked UPSC and judiciary are not hard if  you prepared good for it

But if we campare  according to question then UPSC have vast variety of questions, and have wider perspective

In judiciary it depends on which field you choose as a career it may be heading towards judge, magistrate , lawyer , etc

every exam is hard if you don't work hard

And every exam is easy if you do work smart

UPSC  has its own position and judiciary has its own very thin line different that we cannot differ hardest exam which one is it ?