I have a couple Mini30s. When they banned the AK and all the variants up here 20+ years ago, it became a "go to" rifle for all of us with a lot of x39 ammo already stockpiled. The SKS is very popular up here, but it is what it is, a good rifle in the $200 range. Until the VZ58 and CZ858 rifles snuck in here under the regulations as "non restricted" firearms, the Mini30 was the only good 762x30 semi option that was detach magazine fed. Plus since the new Liberal gov is trying to prohibit class the CZ/VZ rifles right now, the Mini30 has become even more popular, yet again.
I have a stainless poly stock and a standard wood Mini30. I really, really like them, honestly next to a good AK, as in Rifle Dynamics or other higher end AK model in the say $1000+ ish range, I prefer the Mini30 for my mag fed semi auto x39 rifle for numerous reasons. Very comfortable and pointable rifles, really decent accuracy despite what you will read online IMO (like Lazs mentioned, it can be hit or miss from the factory), very reliable, great ergos, ie charging/clearing the rifle is much more positive, again IMO, than any AK variant rifle.
I would seriously consider any Mini30 as my primary 762x39 rifle if I couldn't get access to my Rifle Dynmics AK, which since it's with my uncle and cousin at their place in Scottsdale, a long, long way from Canada, my access is for only when I'm visiting family stateside. AKs are still prohibited class up here, which leaves me the CZ, VZ, and SKS as the autoloader options, that or AR x39 uppers, which are still restricted class like handguns, which means range only and tight transport/storage regs.
If you plan on shooting commie surplus steel case ammunition, you probably should look into some spring changes and some guys change out pins too. Only way to know is to shoot the rifle with the surplus ammunition, and see if you get any stoppages or failures.
Really like the Mini30, you can't go wrong for the $ IMO with the OP pictured Mini. Get yourself some hi cap mags, and if as you said you want to install a pick-your-weeny rail, put a decent red dot or out to 300meters 4x class magnified optic. Promag makes reasonably decent metal 30 round mags for around $25, Ruger's 20 round factory are about double in cost, both work well for me, even with the stupid pop rivet 5 round "legal" pins in them.
Some good pew pews then.