Loose powder will result in better consistency and accuracy. If you measure loose powder correctly you will load the same amount each time. Pellets are more of a convenience than anything else and can be as much as 10% off by weight. That difference can affect accuracy. With that said, during hunting situations the convenience of pellets (in my opinion) out weighs the advantages of loose powder. Typical hunting situations require shots in the 50 to 75 yard range. At that distance you most likely would not see much difference in accuracy between pellets and loose powder.
If I am at the range for a day of shooting, I use loose powder (pyrodex) as it is much cheaper than pellets. During hunting however I opt for the convenience (and faster re-loads) of pellets.