I met her after the Van Vleck Competition in 2006. All three judges, Roberts, Calabresi, and Sotomayor, were great to observe during the competition. I can't really recall tons of details about the competition now, sadly. I do remember Calabresi was actually the one who impressed me the most during the competition, although all were impressive. But I met them all afterward, and Sotomayor was interesting to talk to. I certainly don't have anything specific against her, and remember thinking positively of her during my one encounter with her.
Naturally now I've gone and done a brief search for more news on the nomination. I think it's interesting that the first thing I find is articles about her ethnicity (Hispanic), and whether her ethnicity should be a big factor in the decision of whether to make her a Justice, because people assume it might affect her decisions. Honestly, until I went and searched for articles, I didn't even think of this issue, and I've actually talked to the woman face-to-face. I mean, I understand how it comes up. It always comes up. Race is always going to crop up in these discussions. But really, unless there's some compelling reason to make it an issue (which I haven't seen yet), it should not overshadow the real question, which is, will this person uphold the Constitution and rule fairly on the cases brought before the Court? And we should be able to look at prior rulings, her judicial history, etc. to try and deduce the answer to that.
I also find it interesting that she was nominated to the U.S. District Court for the Southern District of New York by George H. W. Bush, and nominated by Bill Clinton to the U.S. Court of Appeals for the Second Circuit. So both the Republicans and the Democrats have supported her in the past.
It will be interesting to see how this plays out.
Wikipedia entry on Sotomayor
The White House Press Office: Background on Judge Sonia Sotomayor
Huffington Post: Sonia Sotomayor, Supreme Court Nominee: All YOu Need to Know
The New Republic: The Case Against Sotomayor
CNN: Sotomayor Nomination: Is It About Ethnicity?
Feel free to find more articles on your own. This was just what a quick search brought up.