I use 5.8.0 everyday.

Generally speaking, YES. I give you three biggest benefits I get from it:

1. A better support for Unicode, now you can use Unicode in hash key, regexp etc. You can expect more improvement in the future.
2. A much better support of thread, now you don't need to use fork everywhere. A big improvement. I love it.
3. Layered IO, you can use it to alter your descriptor's behavior, a very neat design, for example, you can insert a ":utf8" layer in between, to make your descriptor UTF8-aware.

Some bugs reported, but overall, it is good. Bugs? well they are in every program.

;-) The purpose of testing is to find out bugs, not to prove the program is 100% correct, which, in theory, has been proved to be a mission impossible.