I agree it's the best way to tell if the candidate is a fit. But, I think resume + phone screen (or 2) + an on-site can be almost as good, and not limit your talent pool. The on-site could even include working with the team. What you describe would require me to take PTO from work... to work. Sure I'm getting paid, but I'd tell you no thanks. Others without decent PTO and full-time jobs wouldn't even have that choice