FN FAL " The Right Arm Of The Free World" is the way to go. They are alot of fun. I have never had any problems with mine since i built it. You can get mags fairly reasonable at gun shows. Worst part about it is the price of ammo.
If an M1a1 or HK 91 needs work, you gotta see a smithy. If a FN/FAL needs work, you can do it yourself. Even if you buy a clunker FAL, it is easy to get it to work and the parts are easily available and cheap. The only things you can't do to a FAL without basic hand tools, is to change a barrel or head space it. Everything else is plug and play.
Out of the M1A, FAL and HK type rifles that I've owned, I have to say I like the PTR the best. I still own my M1A and PTR, I sold my Hesse receivered STG-58 a couple years ago. The M1A seems to beat me up a little more than the PTR. Steer clear of the cast aluminum receiver FA91's, I haven't heard much good about them. I know that if you have receiver problems they are extremly hard to fix.
I'd have to say that overall, I'm leaning more towards the FAL than anything else right now. Seems like guys that own and fire them have little or nothing bad to say about them.
That, and good lord have you seen the prices on M1As right now?!?!
Going to continue gathering intel, and when it gets closer to buying time, I think I'll grab some ammo and shoot Thumper a PM. I know I like the FAL, but I really don't want to jump if I have the chance to shoot an M1A before I commit. This will likely be the most money I've ever laid out on a gun at one time, and it'll be a long time after before I can do it again.
FN FAL all the way...But these choices are sooo hard to make. Don't listen to any of us and just get both, the only reason you should take the advise is which to buy first but they are both definitely worth having.