RE: MG and eating eggs, yes they are safe to eat. I never really thought about it before (kind of one of those, 'Golly, I hope so!' type of things, since we've continued to use eggs from the girls), but I knew I had seen it somewhere that it was mentioned and pulled it up just now to confirm. The only time an MG-carrying flock's eggs should not be eaten is if that flock is being treated with some sort of medicine, as is the case for any flock being treated.
Why keep a flock with Mycoplasma Gallisepticum? For me it was a matter of the heartbreak involved in culling my flock. These are my beloved pets, some of them know their names, most come to me just to hang out, some even beg for time in my lap. I've known enough chickens over the 10 years I've raised them to know how varied their personalities can be. Could I get the same breeds? Yes. But I could never replace the individuals of those breeds that make my flock what it is. I don't believe them to be a replaceable commodity in my situation. My choice may have been different if I was breeding them and selling birds, as I would ethically have to restart if I wanted to continue doing so.
There are several sources that are now saying there isn't much of a point in culling and starting over when it's just MG. MG is believed to be in as many as 80% of the backyard flocks in the U.S., and some estimates are even higher than that. That is a statistic, by the way, that I never gave much credit to before I knew it was in my flock, but then my birds had never shown any signs of carrying MG and I would never have known if I had not gone ahead and tested them. As mild as MG can be, who can say without frequent testing that they don't have it in their flock?
I'm not saying, of course, that people should be lax with their biosecurity measures when their flocks test positive for MG. To me, that's like saying everyone is bound to get a cold eventually, so I'm not going to bother covering my mouth when I cough or sneeze. I don't know whether anyone else in the area has MG in their flock or not, so I take precautions with my carrier flock to make sure I'm not responsible for causing its spread. Biosecurity is a bit of a pain, but the effort is worthwhile. If you have a clean flock and want to keep it that way, you should practice biosecurity as well to keep things out, as not everyone with carrier flocks is as considerate when stopping by the feed store or going to swap meets and shows. Just some things to keep in mind.
Edited to clarify something