If it comes down to talking about method of construction and being "essentially" milspec, that itself being an oxymoron, then you are missing the point of his question. You are thinking of the technical aspect of the rifle, he is asking about the functional aspect of the rifle. (with the exception of the token sniper reference, which every thread about a M14 needs
) They both operate off a Garand action, they both come with iron sights, they both shoot a 30 caliber bullet from a detachable magazine and neither of them is an AR.
To address your question...
Accuracy: How much difference is maybe an inch going to mean to you at 100 yards? Do you plan on shooting this mainly off a rest? If you are shooting it free hand you aren't going to notice any accuracy difference at all.
Reliability: Minis are very reliable.
Weight: 6.75lbs vs 9.3lbs. How much of the time do you plan on carrying this around?
Ergonomics: Both are good and both are different in dimensions. If you can get used to one you can get used to the other.
Bang for the buck: Obviously the Ruger has the edge here. Cheaper to buy, cheaper to shoot.
In my mind there are two things you should look at when deciding which rifle to buy. First, how often to do plan on shooting past 300 yards? The 7.62x39mm does just fine within 300 yards for paper and 100 yards for deer. Secondly, how much money do you have set aside for ammo? 7.62x39mm is always going to be cheaper than 308.