You do NOT have to be affiliated with Scouting in terms of managing a troop or den. You do have to sign up as an adult volunteer and do YPT, Youth Protection Training online, every 2 years, but again, that is not a commitment to a trip, den, council or camp. YPT takes a couple hours online every two years. Past that, commitment level is your choice.
While I do like that 4H is working with kids, the fact is there are far, far more kids in Scouting. Couple that with the fact that 4H has it's own certification that is recognized only by 4H and NOBODY else and the question then really becomes "who is more active in your area?"
In our program, we chose Scouting for that reason. Our group of instructors are affiliated with Scouting as I've outlined previously. We go to camp one day per week while it's in session and that's 6 sessions in the summer. None of us goes to any troop weekly meeting. We will hold events for Scouts when requested outside of the camp schedule. The fact that our certification is recognized outside of Scouting means we can also work with Royal Rangers, Trail Life, Girl Scouts, Demolay, etc, again, something you cannot do with the 4H cert.