I used it with great success on my older vehicles that had over 150k miles. It's good stuff in the right situation. The synthetic version is thinner, but is twice as expensive.
I don't think it's a good idea for the Focus because of the extremely tight- like race motor- journal clearances. From what another FF told me, there have been late model Fords coming in with worn out cam bearings due to using thicker than recommended oils. I like using thicker oils for increased compression, better ring seal- etc. With the Focus though, stick to the recommended weight or thinner.
Amsoil, Royal Purple, Torco, SynLube, and others make exceptional synthetic oils. If you prefer using off the shelf oils, I'd go with a Havoline over the Mobil Synthetic because it scored better in the tests that I read on the Amsoil website. It's the closest to Amsoil.