Yeah, I spent hours copying these programs to the computer. I remember one huge machine program listing (I think it was for a graphics program) that had a line with a wrong checksum printed. Without a correct checksum, you couldn't go on typing. So I changed one of the hex values until the line passed... The final program was kinda buggy but I never knew whether my change was responsible for one of the bugs or not.
So you could be pretty sure that your programs worked afterwards.
Nothing beat the feeling to type a program and then finding out that the game sucked.
But in one of the magazines there was a drum computer for the C64, which was pretty cool (forgot its name).