testing or unstable?

[Rodolfo Medina <rodolfo.medina@gmail.com>]

I've been using Debian for more than three years now, but always using the
official DVDs of the most current stable version: first Sarge, and then Etch.

Recently, many times I've been needing to use a testing/unstable Debian version
for many applications that were too old in stable Debian, so now I'm thinking
of switching to a testing/unstable Debian version for good.

Now, my question is: which one is more advisable, testing or unstable?

Excuse the basicness of my question, thanks for any reply
Rodolfo