Hair color & funky hair growth question

I just wanted to know which brand of permanant hair color everyone thought was the best? I have currently been using castings, but my grey's will not stay covered! So I thought that I should try permanant color. I was also wondering if some people just cannot grow their hair out. My hair is so funky it's unreal! It looks great when it's about to my shoulders and then after that it starts spliting all the way up the hair shaft! It's really something to see! I try and take the best care of my hair, but it's like it's determined to split. I've tried cutting it all off, but it grows back the exact same way. I just don't understand it. Any comments will be appreciated! ~S