The 128D was a nice machine, I had one. I did some programming in 128 mode which was a lot better than the c64 mode. There should have been more 128 support software. Developers could have released games and apps that would use 128 features if detected. It was like the amiga scene in the early 90's, having a 3000 or 4000 but having to run (a500) software that didn't take use the extra cpu and graphic power.
The 128D was even better than the original 128. The separate keyboard and desktop case made it more comfortable to use.
