I have a dual format kit (5DII/7D) and tend to use my 7D while walking about. I have the telephoto end well covered with my 70-200, but find that my 24-70 often isn't wide enough on my 7D, hence the need for a wider zoom. I think that the 15-85 would best suit my needs (informal portaiture of my kids, landscapes, nature), and I have an opportunity to get a like new copy for a little over $500. I know it's slow, but it will be used outdoors in good light. So I'd appreciate hearing about the experience and thoughts of people who've used the 15-85 for applications similar to mine.