You probably never want to use an unbonded polyester batting. Bonded means the surface has been treated with chemicals (resins, I think) to prevent the polyester batting from bearding.
I would consider traditional batting to be 100% cotton -- like Mountain Mist Blue Ribbon. This is from before the days of polyester, bonding, and needlepunching (Warm & Natural is needlepunched through a scrim). MM Blue Ribbon is actually my favorite batting for machine quilting; it seems to get softer with every washing and lasts forever. For hand quilting, though, I would use Quilter's Dream which is needlepunched (but not through scrim). Needlepunching of cotton makes it very uniform and stable and easier to hand needle than traditional cotton. MM Blue Ribbon is harder to hand needle because of uneveness and there also seems to be additional drag on the needle -- perhaps from oils left in the cotton.
There might be a traditional polyester batting but since I tend not to use polyester anymore, not sure what that might mean.