The lens you mention is not very fast. If it wasn't IS it could only be used in bright full light. It has a plastic and loose feel. It also has a nasty habit of drifting open [extending] under it's own weight if hung on a strap. I find it a little soft on the range of 200 and up. I have purchased severl lenses since to cover this range and I do not use it very much. It stays at home and sees duty when I want a light lens. Some one will come along and tell you this is a good lens but it aint so!
Here is a shot to show that it is a little soft.