...I'm the Leader of the Gang (I Am)!!! I know - Gary Glitter has fallen long and hard, but it's still a great song and appropriate for today - Gartner has placed Sun Java System Access Manager in the leader quadrant of their Magic Quadrant for Web Access Management, 2H07 [PDF]. I happen to think that they have under-rated us somewhat on our completeness of vision, but I can't argue with the rating on ability to execute.
One thing worth mentioning is that one of the 'cons' listed for Sun - "Sun does not support ADFS/WS-Federation in its federation tools" - will be addressed in the next release - Federated Access Manager 8.0 - and is already in OpenSSO. So, if your existing infrastructure leans to the MS side, but you need world-class web access management, federation, identity web services and more, scoot on over to OpenSSO and take a look.