Wouldn't touch them with a 10 foot pole.
1 they are religious based and will not represent you if you are not Christian. They indorse many non-homeschool actions that are anti equality for women, minorities, same sex couples etc
2 they do not accept relaxed or unschoolers. On their application you must explain your curriculum and give explinations if you do not follow a regular school at home approach during typical school hours etc.
3 they will only represent you in matters against the public school system/government. They will not represent you in domestic matters concerning homeschooling
4 parts of their agenda/sponsoring of bills would make it hard for those who do not follow a strict school at home regime
http://www.homeschoolingislegal.info/