The FM will probably have a longer life due to its all mechanical operation, Another excellent value older camera, if you can find one in good condition....the Canon Ftb, and the older Canon breechlock lenses are excellent value
My story: Back in 1978 I was told I could use some of my Bar Mitzvah money from 2 years prior to buy an SLR since I was so interested in cameras and photography. My dad takes me to the city (San Francisco) to the strip of photo stores that used to line Kearny St. We go from shop to shop and finally decide on one that seems pretty honest. My budget only allowed a Pentax K1000 with a 55mm normal lens and a Vivitar 200mm lens (the latter of which was what I was going to use for all those tele shots I would get published in National Geographic!). However I remember lusting that day after the Nikons in the glass case and wishing...one day...one day.
I stuck with the Pentax for a spell until the early 80's when I finally made the switch to Nikon and got a decent used FM2. Though I REALLY wanted the F3 darn it! At $2000 or so for a new F3 body that was NOT going to happen for that 22 year old!
Anyway, years later (maybe 10 years ago?) I sold off my Nikons (FM2 and FE2) and went Contax for my SLR kit (RX, RTSII) loving the Zeiss glass which was going for a song then since so many peeps were going digital. Then a year or two back I saw a gorgeous brassed-up black F3HP for less than $200! I had to have it. Long story short (too late?): I still love my Contax system but have since obtained in addition to my F3HP a nice early FM2 (titanium honeycomb shutter!) and a whole slew of gorgeous 60's F glass, some gotten for as little as $15 each!
Now I'm trying to stop myself from buying an old F or FE which for some reason I still want! Classic Nikon glass with classic Nikon bodies is so terrfic for B&W work.
"Well, my photos are actually much better than they look..."
About 2 years ago I got my first Nikon in a thrift store. I got amazing deal - F3HP with AI-S 50mm 1.4 for just $15.. The first thing that amazed me was F3's viewfinder - I have never ever seen anything like that after and before. I like OM1's one, but on F3 it's just unbeatable. Somebody wrote in other thread that it's almost 3-D, you can feel space with it and I'm completely agree with that. Unfortunately my F3 has some defects - light meter does not work and backup lever stuck but it does not make it less valuable for me - I have great 100% manual camera. Shutting with it is always adventure and joy for me... And yesterday on big auction site I got 2 other Nikon's I always wanted - FE and older FM2.. Can't wait now.. So exited...