I've played around a bit with TIC-80, but I always find myself going back to Pico-8. The larger resolution is nice, but I find in a weird way I'm able to do more with the stricter limitation of Pico-8 than the more lenient TIC-80. Take the sprites for example, Pico-8 you're locked into the same 16 colors all the time (there's actually another secret palette, but it's a bit of a hassle to use), where as TIC-80 you also have a 16-color palette, but you can change those colors to be anything you wish. I find that additional freedom to be almost paralyzing, and many aspects of the system are like that for me.