Is a C128D rare stateside?
I don't think I'd go so far as to say rare, I'd say more like uncommon. With the internet you can find them ocasionally on eBay where they usually still sell for ~$100 or more in good condition.
The C128D had a 64K VDC(80 column vid chip) where stock flat C128s had 16K. This was a big deal for the few programs made to exploit this chip.
BTW the slap was just a joke. I respect all old school computers, just felt compelled to relive the old rivalry:-P But between the 2 I'd say the C128D is an easy choice, very easy.