Since you asked:

http://www.the-gleasons.com/powerbelt_page.htm

I am in the hater's camp, others are in the lovers camp. You will hear from both. They work at low charges (i.e <= 1400 fps). I like Noslers, Barnes and Gold Dots, Hornady XTP for plinking.

As for loose powder or pellets, the loose is better since you can get an accurate load. Also the pellets cost a lot more, but they are easier for new ML hunters.

Chap Gleason