Seems like you have some great answers from u/thanks_themanagement, so I will provide some insight from my perspective. I was in a civil service role where I worked closely with and supported FMs before I became an FSO. I was hoping to become an FM if I didn’t become an FSO.
The biggest pro, to me, is being the person at post that literally keeps the lights on. It’s something that perhaps can’t fully be appreciated until you work in an embassy, but knowing the work I did had physical results was great.
The main problems I observed (from the headquarters perspective) are not unique to this position - resources. There are over 275 overseas posts and not enough FMs to go around. Because of this you are sent to where the need is greatest. There’s no such thing as a sleepy post for a facility manager. I (personally) liked this because there was a way to make a real difference everywhere I went.
Though you are the facility manager, you almost always have a large staff of locally hired employees and/or contractors. I say this to say that the job is more management than anything else. Technical expertise is obviously valued but you will rarely need to be the one fixing something. This job can be very rewarding if you’re ok with that.
Hours are regular embassy/consulate hours but you’re on-call. I personally feel that what you read on Glassdoor about being stuck on-site is wildly overstated. Yes, stuff happens, but work-life balance is about as manageable as many other jobs in the FS.
I’ve been to dozens of posts and have had wildly different experience at each. That’s the best part IMO, it’s not boring.
If you qualify, please apply!