The 7.62X39 and the .30/30 cartridges are are better compared in bolt action rifles so that the arguments over semi-auto vs lever action doesn't muddy the water as to which is more suitable as a hunting round. Frankly, the .30/30 has the advantage; it propels a 150 gr bullet faster than the 7.62X39 does a 125, and a 170 gr faster than the 7.62X39 does a 150. That doesn't mean that the 7.62X39 is unsuitable, it just means that the .30/30 has a ballistic edge, and I know of one incident for sure where a moose was killed as effectively with a 7.62X39 bolt action Ruger as it would have been with any big case .30. However, IMHO, that falls under "just because you can doesn't mean you should." But for someone wanting a short light deer rifle that doesn't kick too hard, or bark too loud, the 7.62X39 has something to offer.
When it comes down to the choice of sporting rifle, now we get into the semantics of personal preference between action types. It can be argued that both a semi-auto and a lever action can be emptied faster than a bolt action, and the semi-auto manages it without the firing hand breaking its grip. But at this juncture we need to consider the specific rifles we are referring to. The .30/30 is most frequently encountered in a traditional lever action rifle, with the best examples usually being the Winchester and Marlin offering, but it can also be had in a hinge action single shot, a bolt action, and a pump. While the 7.62X39 can be found in Ruger and SAKO bolt guns, it is primarily found in semi-auto carbines of the SKS and AK family, although there are some AR-15s chambered for it now. The advantages the AR-15 has over the SKS does not benefit Canadian hunters wishing to carry a gas gun, unless we can get the classification of firearms changed or rescinded. But the difference in practical accuracy between an SKS and an AR-15 is astonishing, if my AR is representative and my experience with SKSs and AKs is typical. These carbines are designed to dominate a fight across pistol ranges and they do so effectively, but I've yet to encounter one that I would want to shoot at a live target with at 200 yards, and 200 yards is still within the envelope of the typical .30/30's capabilities with a good marksman on the trigger.