...Each of the three has a different background, and each has taken positions that respond to different circumstances. Both Garland and Wood are judges, for example, but they have decided very different kinds of cases when it comes to hot-button issues: only Garland’s docket includes decisions relating to the war on terror, while only Wood’s includes cases involving abortion and religion.
We can infer a little about the three from their professional choices about their respective career paths, which do support the conventional wisdom that they are arrayed left to right: Wood, Kagan, Garland.
But the distance between the three seems not to be dramatic. Garland has spent most of his professional life as a public servant, including (like Sonia Sotomayor) time as a prosecutor. He is in that respect a model judge, truly balanced...
All of the points above explain why the choice between the three front-runners is a difficult one, particularly when the additional factor of politics does not seem likely to play a decisive role. It is obviously unclear who the President will choose, but on the merits, I think it is most likely that he will turn to Elena Kagan.
http://www.scotusblog.com/2010/04/selecting-stevens-successor/emphasis added.
Though Garland is considered the most conservative Goldstein believes that he fits comfortably within the Liberal bloc. Remember that Breyer was also considered more conservative on criminal justice issues. He has turned out quite well.