My 2¢
Great guns!! Mosins are cheap, simple & relatively easy to clean. Very few moving parts = very reliable, as long as you clean whatever they put on the guns to store them - most from a Big 5 will be straight from surplus storage and need a thorough wipe down.
Pros
-Accurate as hell - iron sites can get you 700+ yards once properly sited
-Cheap and thus replacement parts are cheap, plus sportster (new, light weight) stocks are pretty common and easy to come across if you want to get rid of the wood stock
-Strong. The 7.62x54 (known in the US as .308) will take down some pretty large game - anything under 600 or 700 lbs wouldn't stand much of a chance.
- Stripper clips - a thin piece of metal made for quick reloads, put right above the open bolt & push the five rounds down in to the clip. Russian stripper clips are the best, though a bit rare.
-Made for war - Many don't agree but I personally find that guns made for war are stronger, sturdier and simpler, all plus's in my book. Recreation rifles can be finnicky and over designed.
Cons
-Old rifle = old hardware. Sometimes you have to muscle those bastards through a round, which means piecing it apart, sanding it down to a fine shine & refinishing (or just muscling through it

-Heavy - if you plan on hunting, know that the ammo is heavy and so is the rifle. But that makes for much more damage per round.
- Loud - All guns are loud but these things SCREAM - even send a 2ft firebolt out when shot at night, so very easily spotted by site and honed in on by sound.
- Kick like a mule. You can add rubber stoppers & such to decrease kick (which definitely help) but be ready for some bruising on your shooting shoulder after a couple hundred rounds.
- Most scopes get in the way of stripper clips. Only the Scout Scope, mounted in front of the bolt, allow for stripper clips.
Over all a great gun, especially for the ridiculously low price. They fly off the shelves when stocked in stores. Really popular. Great for hunting or as a back up/give to a friend when SHTF. Can't go wrong with a Mosin. Happy hunting!