5k US is a hefty chunk of cash. For people who use the DSR for daytime too of course, the 5D is quite a camera.
Recently I went full CCD with the Qsi583ws which has the same chip as the SBIG 8300. This is quite a bit cheaper than the 5D but of course only for AstroPhotography. Non filter wheel version about 3k US. I have found the ability to set the CCD temperature and know it is quite regulated to be handy to avoid issues with real dew-laden nights. Also very much like the built in filter wheel which if you take flats the slight vignetting is not an issue (my lens is f/2.8 is why the vignetting).
I completely love it and have started with some autoguided widefield which makes it to
www.astrospotter.zenfolio.com if they are presentable enough to make the grade.
The beauty here is I put my Canon 200mm f/2.8 on it (with an adapter) to take advantage of some nice Canon lenses I have. I get a 5.3 x 4 degree field. I like the results. The far corners are still acceptable even at f 2.8. I don't stop it down cause any stop down gives those 8-point stars that I hate. I will be trying the round homemade mask for stop down next month.
After I feel ok with this I will hook the thing up to my Williams Optics FLT110 but need to get a very firm mount before I mess with that.