It's one of the greatest battlefield firearms of all time.
I have 3 myself... two of which I put together at home from parts kits.
Pros...
It's an ingenious, elegant, simple design (Ok... so it can be claimed that the Germans came up with it first).
Reliable... easy to disassemble and maintain... parts are readily available.
Spare magazines are plentiful and inexpensive (75 and 100 round drum mags are also available).
Up until a few years ago, ammo was also plentiful and inexpensive (1,000 rounds for under $100.00)
Cons...
not very accurate (crap beyond 200 meters), 7.62x39 is underpowered for a .30 caliber round (since replaced by 5.45x39).
Every gun owner should own at least one.