The 55-250 has IS; the 55-200 does not. And, what do you mean "does it work the same"? You need to understand focal length, then you will know what lens you need.
Wrong. Both are EF-S lenses.
Hi guy,
please kindly refer to page 109 for EF lens work III.
EF55-200mm f/4.5-5.6 II USM is for EF mount.

I do not think that there is any EFS 55-200mm.
Please kindly correct me if I am wrong.
thanks for your visit to this club thread also although u r not 450D user.
Do share with us your 'correct' knowledge and we welcome all useful information.