I use them on all my systems. Reliable, cheap and long lasting compared to MSR.
Only downside is the fixed length of 10 digits for the pin which is because the cheap basic ones only use the RFID serial/id rather than a data string often used by higher prices mayfair type higher frequency ones.
Which means its not a number you can remember and type in if forget you fob.
In my local system it works well as prevents users from learning what the 'manager' pin might be to void things.
Although never any issues like stealing it was more that they messed stuff up rather LOL
Only snag for me personally is using tablets as no easily attachable raid reader so will have to setup a second user for each hostes to be able to login the tablets.