hey there!
There aren't any "good or bad" mutations. They're all mutations, so they're all technically bad. As far as one being worse as opposed to another, it really depends on the person. I have DDF508 and so did a friend of mine growing up with CF. He was VERY sick. From about 5 years old and on, we didn't see each other because of his health. He unfortunately passed away at age 22, from many CF complications. I, on the other hand, have been relatively healthy all my life. I'm only now starting to get more and more severe CF symptoms. Same mutation, very different effects.
You may hear that DF508 is a bad one, but that's not proven. It is, however, one of the most common mutations in CF. I think a lot of people tend to associate the fact that it's so common with it being a "bad one". Like I said, I don't think that's been proven. If I'm not mistaken, one of the "elders" on this forum (above age 50) has the same mutation as you and I...so that just shows the difference in people even more.
Hope that helped. <img src="i/expressions/face-icon-small-smile.gif" border="0">