I started scouting in 6th grade -- just about the time girls are dropping out. I loved it. I had great leaders who took us on great trips and taught us a wide variety of things. My best experiences, however, were during high school: I went on several "Wider Opportunities", which means experiences beyond the troop and the local council. I traveled cross-country with a scout group, and I went to the international scout center in Mexico.
I can honestly say that every single day I use SOMETHING that I learned in scouting. When my kids have birthday parties, we play games I remember from scouting. When I sing to my kids, it's my old scout songs.
All troops are not created equal, and MUCH depends upon your leader. Find out how often they'll camp (or do other overnights -- for example, my troop is doing a museum-sleepover soon, others do zoo sleepovers, etc.). Find out if they're family-friendly (are you allowed to stay for meetings, invited to campouts, etc.? and do the answers match your idea of what's right?).
I do suggest that you register with the troop. If you drive on field trips, etc., you'll have GS insurance. $10 well spent.
Here's my impression of each level:
Daisies: I'm not a big fan of the Daisy age level program. Because the kids only stay in the program for one year, it's almost impossible to get any continuity of leadership (because leaders move up with their own daughters as they age up to Brownies). The program is essentially a playgroup. Daisies have many limitations on what they can and can't do.
Brownies: Brownies is a great program. The kids can earn Try Its (brownies speak for badges). They can camp overnight, the council offers LOTS of great programs for them, and they love being together. My girls are going to a program in a few weeks called "Escape School" -- it's about stranger-danger and kidnapping. It costs $1 per girl. Later they're going to a science program called "All About Reptiles". All this is offered by our council. Brownies emphasizes. All scouting levels stress the importance of age-appropriate community service. Over half the GS in America are Brownie-aged.
Juniors: Juniors is even better than Brownies. The girls begin to take on some leadership responsibilities within the troop. Because they're older, they're able to do much, much more. The badge program is really beefed up from the Brownie level, and there's the Bronze Award for girls who are very involved. I don't think a girl could realistically do everything the Junior program offers in only three years. My Junior troop just went to Savannah to the birthplace of Juliette Gordon Low (founder of scouting). In addition to visting her house and learning about life in the Civil War era, they spent time on the beach, went on a dolphin cruise, went on a carriage ride and a ghost tour and ate in nice restaurants.
Older Girls: This program is currently undergoing serious changes, and my own girls aren't there yet, so I'm not the best one to tell you about it. The terms Cadettes and Seniors are being phased out. Still, these girls have SO MUCH to do! This program offers multiple leadership-training opportunities: some specific to camp, some for troop leadership. These girls earn Interest Project Patches instead of badges, and a new range of "charms" is just being introduced. The award topics are contemporary and appealing to today's kids: Emergency preparedness, Scrapbooking, etc. These girls should be allowed to run the troop, with adult leaders acting as guides and safety nets. These girls can travel internationally, they can take part in council and national scout leadership. This is such a great program; sadly, the great majority of girls drop out before they reach this level.
Regardless of the level, scouting is an inexpensive activity. Registration is $10/year. This goes to National to continue program development and to pay for scout insurance. Most troops charge yearly dues of $20-50, which pays for meeting activities and badges.
Scouting is an activity that you can sort of take "at your own level". If your daughter turns out to be like my girls and LOVES scouts, you can earn badges on your own at home, take part in additional council activities on your own . . . and the opportunities grow as she gets older. Or, you can just attend meetings.
Another good thing about scouting is that it's a "safe" activity for girls in a world that seems scary so often. Recently I heard that a certain senior troop voted to do finger-painting in a meeting. When the leader asked if they didn't want to learn a new craft -- stained glass, or something more adult -- they refused, saying that they LOVE finger painting, and they can do it together in scouts without anyone laughing at them for being babies. Recently at a meeting, I saw a Junior scout get up and give a small gift to several other scouts who'd helped her at a council event. The girls were all sitting at a table taking part in a craft, when the girl suddenly became ill. When she stood up, she passed out and hit the floor. The other girls at her table (not from her troop -- this was a council event) jumped up and treated this girl as a "sister scout". One girl ran for her mom, who was the event nurse, and the other girls moved chairs and tried to help her. Why'd the girl publically acknowledge their help and give them a gift? She said that she knew that if this'd happened as school, people would've laughed at her -- instead, her sister scouts came to her aid. That's the type of girls I want surrounding my daughters.
If you have questions, please ask. I've been doing this almost 3 decades, and I'd like to think I have the answers.