In my experience, I like them in a general sense. Utah, at least my area of the state, is full of them. Some are company-founded, but there are just as many if not more of the grassroots type. I came from teaching in the traditional public sector myself and like that system, but I do admire the diversity of charter schools and the choice it gives parents.
I suppose the key is to be wise and to study the schools you're considering, whether they be traditional public, charter, or private. I don't think the school's category in and of itself determines the school's worthy.