Now that the Perl repository is stored in git, 5.10.1 should be out soon. 5.10.0 is as production ready the day it was released as it's now ;-) (The previous sentence doesn't voice an opinion on whether 5.10 is production ready or not - but 5.10.0 is either production ready for you, or it isn't; perl versions aren't like wine or cheese, they don't ripe over time).

As for me, in some environments, I run 5.10; it's "production ready" for the tasks it's needed it for. In other environments, it isn't. And some environments will stay on 5.8.x. The cost of testing whether everything will remain working on 5.10.01 doesn't outweight the benefits of switching.