Authentication: Ion or Tank?

[eluser]David Hyland[/eluser]
Hi there. I'm about to embark upon my second build in CI and have been pre-researching auth libraries. Last time round I used the simple Erkanauth which worked nicely just for authentication but this time I need something a little more rounded.

From my research I have narrowed this down to Ion Auth and Tank Auth.

For those of you who have used either of these libraries, pros and cons? Any clear winner?

Cheers!

[eluser]David Hyland[/eluser]
UPDATE - Thinking about it, are there any auth libraries out there that already support 3rd party login (google, facebook, twitter, flickr, etc)??