You have to realise that since this is an EF-S lense, it can't be used on a full frame camera and can only be attached to cameras that supports EF-S such as the digital rebel series. Furthermore, with crop factor affecting the actual range of the lense, you'll probably get an equivalent zoom range of 80-400mm. Not having the wide angle range is a bummer but I could live with that. It's lightweight too.
The samples below are photographed using the Canon EOS 400D with the Canon EF-S 55-250mm f/4-5.6 IS lense except the first one.
It has IS (Image Stabilizer) functionality. Incorporating a 4-Stop IS, I could clearly see the difference when I tested out the lense at the shop. 
Canon EF-S 55-250mm f/4-5.6 IS (1/13s @ 250mm without IS)
Canon EF-S 55-250mm f/4-5.6 IS (1/13s @ 250mm with IS)Get the picture? And for around 850 Ringgit it is a good bargain!
Detail is excellent @ 55mm. 
@55mm. 
@79mm. 
@250mm.
@250mm. Still good!
@250mm. Some vignetting appears. Not much of an issue. And at the telephoto end, backgrounds tend to be soft and smooth because of it's circular diaphram. Also not an issue.
Auto focusing is excellent as I track this eagle which flew over me. Excellent lense for the price, not to mention that it has IS.
I'm no expert at reviewing lenses but you could judge very much for yourself after having look at the images!
The next photo has nothing to do with the lense. It's just my ego. That is me with the Nikon D80 and the 70-300mm VR lense. But to come and think of it, it is photographed with my Canon EOS 400D and Canon EF-S 55-250mm f/4-5.6 IS lense.
The next photo has nothing to do with the lense. It's just my ego. That is me with the Nikon D80 and the 70-300mm VR lense. But to come and think of it, it is photographed with my Canon EOS 400D and Canon EF-S 55-250mm f/4-5.6 IS lense.
