I think the Duggars may have some good motives, but I am not a big fan. I do think it's good that they encourage people to be debt free, mothers to stay home with their children, and that they live their Christian witness in front of the cameras and try to reach others. I do wonder how much being on tv has effected them and how their lives will be when the show ends. It will probably be less hectic then, and maybe some of the things I and other people criticize them for will no longer be necessary once the cameras are gone and they can be on a more normal schedule.
OTOH, I don't think it's fair to the children to have grown up in the spotlight the way they have (I don't like any long term reality show with child cast members, not just the Duggars). I also think they place too much of the parenting responsibilities on their children - I'm not opposed to chores, but I think that many kids and the buddy system, combined with the added pressures on Michelle's time with the TV show, books, and speaking events, forces the buddies and the older girls into taking on too many responsibilities of mothering. I am especially uncomfortable with the babies moving to their buddies room so early, instead of being cared for by Michelle, because infants need that time to bond with their mothers.
I also question some of the financial stuff. I'm sure they did have to scrimp more in the past, but they make a lot of money from the show and other things now, and I am pretty sure they do not really buy most of their clothes at thrift stores anymore (some of the clothes on the show are in season, current year, name brands, not stuff that's easily thrifted) - you can see a noticeable difference in their clothes since the show started (I guess a lot of clothes in the earlier seasons was sewn at home). To promote frugality, their cooking and eating habits are very wasteful - yes, it's a lot of pole too feed, but why not use real plates and silverware and take advantage of the nice kitchen equipment. They could also eat a lot less processed and prepacked stuff and more fresh fruits and vegetables, even if they had to grow them their-selves.