Hello,
I also used PBR's on a ISP redundancy scenario, when we configured the PBR's it worked ok but when we changed an existing rule, let's say pbr rule 15, the previous one was not deleted, so checking with ip rule command we had duplicated rule 15, and the new one didn't start working until i deleted manually the old rule 15 with ip rule del command.
So in my experience it works but not very well and as @PhoneBoy and @the_rock told you, not recommended to have an unsupported feature working on production.
Regards