I have never liked bead jigs. While I agree there are alot of different colors and sizes of beads to choose from, the majority of beads float. The natural bouyancy of the beads are working against the lead head to sink the jig. I think you want your jig to be directly under your float or bobber. Adding floating beads allows the current to slightly pick the jig up and carry it. This affects how your line moves thru the water and how your float or bobber floats on the surface...however so subtle. I am talking primarily with 1/8 and 1/16 oz jigs, anything bigger will probably be ok.
Just my observations and my .02