Well, I graduated from a Miranda Sensorex because I noticed how much sharper the photos were from my friends Minolta SRT101. And then I left the Minolta XE-7 when I noticed that the lens I just mounted moved past the click stop on the mount (I was on a job at the time; scared the pants off me!).
Nikons had the reputation for rock solid reliability. For the last 30 years, my Nikons have delivered over and over again.
Canon was of interest at one time, but that was just about when they decided to replace the brass inners of their lenses with plastic. Bad move.
Olympus made great cameras, but the early OM models had very small controls placed very close together. My large fingers got in the way.
Pentax, well they started out on the right foot with their SMC lenses, but somewhere they just lost their way. I remember there being some reliability issues, too.
Contax, Leica, well need I say more. Anyone have a banker for a dad?