I'm coming to this thread late but I can attest to F50s being rock solid
beasts.

Our main patch repository runs off a F50 -- it used to be a SP control
workstation for most of its life. With the SP cluster recently retired,
it's just serving as a very handy large disk repository due to all its
internal disk capacity.

It almost never goes down since it's on an industrial UPS, and the OS
and hardware itself is stable.

Though, our IBM hardware in general is pretty reliable. Usually the hard
drive breaks after about 5-6 years of daily use and for SSA controller
cards, cache battery expiring after 3 years. Rare that anything else breaks.

Hard drive replacement accounts for perhaps 99% of our service calls for
all of our IBM AIX boxes, with the occasional unusual events like where
the first generation 6H1 PSU caught on fire or where the same 6H1 also
blew its motherboard (different event, a year earlier).

-Dan