I've been running Debian 10 (testing) on my main workstation for a few months now and I have been extraordinarily happy with it. Moving to the stable release was as easy as accepting two changes to apt sources, and boom, it's tracking stable. Very smooth and a wonderful experience so far.
@twylo The testing two days ago was the same with the brand new stable.
It just changed the name.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko