Is it worth it?
I’m looking for stuff like grinding ability, sleep time and stability.
If thats what you’re looking for in a yoyo then look no further because the io gets an
A+ in all of that. 
It does use a metric size bearing though, just in case that’s a problem.
It’s worth the money. Smoother than some Genyo even!
It’s a nice throw. Relatively stable, good spin time and good grinds. The one I had was exceptionally smooth