Overall performance (with the exception of burst shooting) is very similar to the EOS 450D, thanks no doubt to the DIGIC III processor shared by both models. There are a few areas where it comes up slightly slower, but generally there's little to complain about and the camera feels snappy and responsive in use.
Continuous shooting in JPEG is an acceptable 3.0 frames per second (with no limit to the number of frames per burst). RAW continuous shooting on the other hand is decidedly lackluster both in terms of speed (1.5 fps) and buffer size (if you've got a very fast card you might get six shots, but with any 'normal' SD card it's half that). Whether or not this is a simple case of Canon crippling the Canon EOS 1000D to put some 'clear blue water' between it and the next model up, there's no doubt that this really isn't a camera for anyone with a need or desire for continuous RAW shooting.