Tak,
The 444, 45-70 and 450 all have killing power at short to mid range (<150 yds) which is phenomenal. Recoil can be pretty stiff too. Big pills with big frontal area and decent sectional density (how much stuff is coming behind the nose of the bullet) equals major penetration and knockdown power capable of stopping and killing ANYTHING in north america at these ranges. 30-30's will deliver a fatal blow on moose at short range, but they lack the knockdown and penetration of the bigbores when things don't go quite perfect on the shot. Having said that, a poor shot on game is no less ineffective with a big bore than with a 30-30 or 30-06.
If you primarily hunt deer with occasional moose, a 30-30 will do. If you hunt a fair bit of game larger than deer at ranges under 200 yds and can handle recoil ok, the bigbores are worth considering. If you hunt at longer range, you will have to consider longer range calibers like 30-06 or one of the magnums and demonstrate to yourself that you are capable of consistently placing shots in the field under pressure at those ranges.
Hope this helps.