They really are nice little machines. Lots of flexibility when you combine the hexbus peripherals and the PCIF from the dockbus world. That gives you the ability to save your programs. Of course, if you're trying to use a newer computer, you'll definitely need TIIF from Peter Engels. See the TIIF 4.0 announcement in this section.
Then again, if you want to use the PCIF, you'll need to build an adapter to go from hexbus to dockbus. Not hard to do at all if you're fairly handy with a soldering iron.
As far as being a dud, yeah, the CC-40 got caught up in the blood letting of the 99/4A. However, it was "reborn" as the TI-74. Slightly smaller physical size, but essentially the same nifty little machine.
If you're interested in building a hexbus to dockbus adapter, check directions at
http://suddenlink.net/pages/curtismc/7495.htm
If you're REALLY good with a soldering iron and want to tackle making your own PCIF, here's the schematic :
http://suddenlink.net/pages/curtismc/PC_Interface.jpg What a person could do, if they were of a mind to, is to substitute a hexbus for the dockbus shown. Then you wouldn't need the hexbus to dockbus adapter. The PCIF is really the only dockbus peripheral that is useful on the CC-40.
Enjoy your new toy!