Mosins are awesome, they're cheap, accurate and powerful. I bought a 91/30 in 2007 and shot it to death (it's got almost no rifling left) now i also have a m44, m91 and ex-dragoon.
I think the one problem with them is that those surplus rounds are really hard on the rifling, from brand new to shot-out it's probably only 5-8k rounds. the other issue is that unless you started with a bright new bore you'll have the time of your life trying to clean it after every range trip, a pitted bore is nearly impossible to clean, no matter how many patches you use it's still dirty! I recently discovered old ww2 surplus GI bore cleaner is probably the best cleaner so far, it'll restore the bore to bright & shiny with only a few patches, vs almost a hundred using Hoppes 9. the old surplus cleaner only effective at removing soot, you'll still need water or hoppes 9 to remove the corrosive salts.
Last i checked J&G is still selling chinese T53 mosins for a cent shy of $100 but they look like crap and really beat up. better to get a nice new (or fairly new) mosin from classic arms for $20 more.
i have two tins of 1947 surplus, non magnetic. then i have 11 tins of 1970's surplus with the steel core and can't shoot that alot of ranges... and 3 tins of bulgarian yellow tip heavy ball that's non magnetic and pretty darn accurate. ammo is pretty cheap and the tins are awesome because you can put them anywhere handy and they'll preserve the ammo forever, when you open one it smells like it just came out of the factory moments ago (not 40+ years).
Mosins can benefit alot from handloading. Not all mosins require a .311 bullet, in fact the loads I did for my ex-dragoon I used Berger .3095 155 gr bullets and they were dead accurate. I think you can use regular .308 bullets for loading, I measured a bunch of my 1970's surplus (pulled bullets) and the bullets are .308 diameter.
The one thing i wish these old rifles had is a chrome lined bore. 2x as hard and twice as long lasting than regular steel and super easy to clean, I won't have to search for ww2 bore cleaner anymore. for example, I've shot alot of yugo corrosive and chinese corrosive in my AK & SKS, both have chrome bores, and they were very easy to clean, only a dozen patches at most, didn't bloom with rust on humid days and after several thousand rounds the bore looks still brand new.
I wonder does anyone chrome line existing bores? probably cost a hundred bucks but if i can have my rifle last twice as long it's worth it...