Eventhough the CSPPC beats the BPPC, it will still be easier to find a BPPC than a CSPPC, since BPPC comes in 12 different versions, the CSPPC does not, IIRC the CSPPC only comes in 4 versions.
@Bubba
Everything depends on what you want to do with your computer. If you only want to upgrade in order to be able to run OS3.9, play games and use SCSI drives, then a A1200 desktop with a Blizzard 1230 board and SCSI kit will be enough.
If you on the other hand want to use the Amiga for the above, and play mp3s, surf the internet, play games like Quake 2, Heretic, etc, etc, you would be better off with an Amiga 4000. Most modern games requires a graphics card (or at least benefits from it) and a PPC CPU, and if you want this on an A1200 you first have to towerise, put in a busboard (either zorro or PCI), but with the A4000 this isn't needed, as everything is in a case that is ready to be expanded.