First, for dragging purposes, I think the 90 degree bend tends to "dig" more as it scoots along the bottom, kicking up more debris as it moves. I am sure each bend has its moments, and I have very little experience with the 60, but its 90 for me.
The second reason, and perhaps the biggest reason of all, is that BOTH my tube head molds are 90 degree molds
I never push the jig-head all the way to the front of the tube. Instead, I prefer to keep the jig-head at least a half-inch back from the front ot the lure. The offering tends to act more erratically when presented like that.
So, with that said, I use a 90 degree angled jig-head because a 60 just can't be effectively inserted in a tube in that manner.
The day before the last federation tourney on Champlain, I bought some 60 degree heads and ended up pitching and casting them to milfoil beds the next day. They seemed to come through the grass pretty well. It's not a technique I use too often, but at Sacket's Harbor this year I was doing a similar thing with the 90 degree head and seemed to be hanging up more often. It may have just been coincedence, based on the fact that they were two different weed beds(both milfoil though), but maybe there is something to it. Has anyone else had a similar experience?
For dragging, I have been using them interchangably this year and haven't really seen one hang more often than the other. I've had 15-20 lost jighead days with 90 and 60 degree line ties.
I dont use either. I prefer to rig my tubes with a wide gap hook and a 1/8 oz bass casting weight riding on the hook shank internally. This already creates a bit of a rattle or thumping sound.
On the occasions that I do use a jig head, I prefer one with a 60 degree angle.