S.B.
Some of my fondest childhood memories are of AWANA. However, I don't think that you could compare Girl Scouts to AWANA - apples and oranges. I sure wish all of my kids could have done AWANA, but sadly only my oldest two did and then we moved to an area that didn't have it available.
Depending on your schedule, you could do both - AWANA was always just one night a week during the school year and usually Girl Scouts is about the same (but has more work that needs to be done at other times so prepare for that). See which one you and your child feel is more enjoyable. Also, the people who run the group, basically make the group, so if you have a "not so good" Girl Scout leader, than your daughter's experience is likely also not going to be so good.
Good luck!