This one was before my time I’m afraid. I do remember seeing a c16 one time, but that’s about it.
I started coding with Vic-20. I think c16 came after c64, even if the name implies the other way round.
Edit: My first assembler codes were done with the machine code monitor in Vic-20 
MOS 6502 assembler was so simple to learn!
A little before my time…but doesent mean I havent got a c64 
Me too! You are right, the 6502 / 6510 (in the 64) were really easy to learn.
are
were for me, They were dead to me when I got my Apple.
ahh aight, I prefer boot to basic era machines
I’ve attempted to write a 6502 emulator before.
The addressing modes always made my head ache,
but the instructions themselves are fairly straightforward.
I also started on a VIC-20 when I was a kid. When everyone else had moved on to C64 instead I doubled down and picked up all the accessories on clearance. I had a 6 Slot motherboard that plugged in and 32K ram cart. I could save the game carts to tape and reload them into RAM and modify them. I finally moved on to Apple II in high school.
Nice … the 22x23 screen size was the only killer there.
I also remember using a RAM memory expansion in the back of Vic for loading game cart games that were stored on tape. I made switches to the expansion to select the memory bank to load the game to. I also had a switch to cut off the write signal to RAM expansion. That was because some cart games tried to write to the cart memory to check if that was RAM or ROM. That was a simple copy protection 
That was also my first brush with copy protection, and I’ve been fascinated ever since.