OKRs only work when they're updated as business needs change.

In one job I've held with explicit OKRs, they worked well because the job remained pretty much the same.

In another job, my OKRs created at the beginning of the year, moved further and further from what I was actually doing over the year. My boss didn't let me change them over time, and by the end of the year, he put me down for not meeting the OKRs. (This gave him an excuse not to give me an annual raise.)

They're another tool in managers' boxes, both useful for actually improving their employees -- or for picking favorites.

They are useful for getting wide company alignment but should not be used for any kind of performance management.

not so great, in a big company where OKRs trickle down you are judged and dependent not only by your own (personal or team) OKRs but also by your sibling teams OKRs- below, above and around you.

This means that you can deliver a successful product and still not be appreciated since another team didn't integrate it on time or did not deliver a crucial part to your team.