I've had servers in FMT1 since 2000. They had a series of power issues. Generators didn't start and everything died. Next time the power went out the generator started and the switch from the grid to the generator blew out the switching system (and killed one of my hard drives and who knows what else) IIRC. I'm pretty sure Linode moved to FMT2 because of this. There have been other problems but around 10 years ago they reached a point where the whole power backup system was new and they have only had one outage that I can remember since then.

We colocated in both Fremont DCs for about 10 years. Their newer one had 2 power outages within a couple months when we were there (I think this was in 2009 or 2008). I don't remember why exactly it happened, but I think for at least one they had redundant power disconnected for reasons. Other than that we had no issues though.

But it's been about 7 years since we've colocated our servers there.