I have never tried pellets so I really can't comment on which is better, but I use loose powder because I see no advantage in using pellets, and loose powder costs a lot less. With the pellets you would eliminate the step of measuring each powder charge, but that's the only advantage I see. Loose powder has the advantage of being able to use the exact load that your rifle shoots most accurately.
If I were you I would try both and find out which works best for you. For loose powder I like Triple 7.