Rear Leafs -- Good/bad?

[Lamah]

This has probably been asked many times, but in the back, are leaf's better or coils ? too me it seems like leafs would hold the axle better since it doesnt need to be able to turn. But as far as better for trails, how much better would coild in the back be if at all and are they worth the money?

Thanks
Jeff A.k.a. Lamah