I have decided I needed a longer reach and with much research, have decided on the F4L non IS. Then my wife goes, "Why get that when u can get the IS version?" Mind u, she doesn't even know what IS is but she says that from what I was telling her, the extra money seems worth it. So, my question is... it is really worth double the money? Some would say go for the 2.8 but I think the weight will turn me off, eventually me not using it as much. Besides, I can up my ISO if ever I need to use it indoors or in low light.