Mardy, I've used 300D (still have it) and 20D (still have it but on loan), and a variety of mono cameras. I've not had a OSC CCD but comparing what I have had to DSLR.
There is definitely a steeper learning curve with the CCD, but most of that is the software rather than the camera itself. If you decide to control a DSLR from a laptop its not much different.
CCD because of the cooling produce a much cleaner image as far as noise is concerned. If you have a regulated temperature then you can create a library of darks which is very handy.
DLSR can double up for terrestrial camera. I hear many people do this
DSLR can be stand alone and all images stored to card rather than downloaded to laptop.