Image Stabilization worth it's weight (pun intended) in gold.

The L series lenses signified by their red stripe or in the telephoto range their red stripe and tan coloring is Canons top of the line lenses. The range on the 70-200 coupled with it's 2.8 appature make this lens extremely flexible. This is THE telephoto lens to have in your bag for those close up shots. The casing is made from durable powdercoated metal to take the blows from running around in the field. Trouble is that because of the housing and the number of glass elements in the lens make it pretty heavy. I highly recommend using a monopod with this lens (use the mounting ring on the lens and not on the camera body). The AF (auto focus) is extremely quick and quiet. The images quality is very sharp. I use this lens with my 20D wich actually makes the lens a 112-320mm due to the 1.6 frame conversion. Pair that with a 2x converter and you have a serious zoom lens. The IS (Image Stabilization) is a big plus on this model. You end up paying around $550 more for that option from the same lens without it. But for hand held or even mono-pod held shots it really helps with clarity. When you put the 2x on there and shooting at 100ISO the exposure times can be around 150 even in daylight conditions and without the IS you will get some blur. There's a switch on the housing to turn this on and off which is nice. Also you have a Macro focus range of either 1.5m or 3m also switchable on the housing. The plastic lens hood is nice. It can be inverted for storage with the lens and seems to be very durable.