Quite a bit of difference, relieve stress points like back, shoulders,wrists, and necks because of either pressure or angle. The drag bars and straight risers on my SM from the factory I found uncomfortable. I put 1/2" taller and 1 1/2" farther back coupled with BA bars and now I sit more upright and arms farther apart and can ride all day in comfort.
Wendy has back problems and I put 1 1/2" taller risers on her BA and I think they pull back about 3" (could be 2" I forget) and the new position went a long way to relieving her back pain.
