Well I've started the program a few times now (I think 3?) and never managed to make it all the way through. I made it through week 3 each time but week 3 was so tough that the idea of moving on to week 4 scared me.
Although I see that Tracy said it gets better after week 3 so I guess I should have just pushed through, haha.
I know a huge problem for me is I live at high altitude, almost 6200 ft above sea-level, and so the progression of the program was just really really intense. I usually would end up doing two weeks at each level (so getting through level 3 meant I had done 6 weeks) and that helped a lot except for the fact that I'd get really really bored of the podcasts, to the point where I dreaded going. The podcasts in general were difficult for me as one of the reasons I like going to the gym is to listen to my own music or podcasts, watch tv, etc and I couldn't do any of that while doing the program. But I have an iPhone now so I'll have to look into the C25K app and see if that helps.
There were other things I didn't like about the program but I don't want to write a novel here.
I do think it will work, I'm just not sure it was the right program for me.