Haha that's cool! :D  Ciao and Sketch work the exact same way. Ciao is smaller/thinner. I have large hands, so I feel like Sketch fits me better.  Ciao also looks a bit "cheap", more plasticy sort of. But they are exactly as good as Sketch. Same ink, same nib :) So there's no upgrade so to speak, just personal preference. 

The only downside with ciao is that it holds less ink, so you would have to refill more often than with sketch. There aren't as many colors avaliable either.

How long before you need to refill highly depends on paper, coloring style and how often you use them. 

If you use thin markerpaper, they would last a looong time. But if you use thick watercolor paper they will run out of ink a lot faster. 

I have 200+++ markers and about 40 refills, and not all are used. One refill package can fill a sketch 10 times (i think) from emtpy to completely full.  I've had mine for about 10 months, and I have used them a lot.