I predicted to myself that watching and listening to this would be painful, and it was. The format made it less of a real debate than the previous (Obama-McCain) one. Partly for this reason and partly because they are vice-presidential candidates, Biden and Palin ended up talking past one another much of the time (as others have pointed out). A bit of the post-debate commentary on PBS was interesting, especially Ellen Fitzpatrick's remarks on how the politics of gender have changed in the last 20-25 years (I'm too tired to summarize them).
Substantively, Biden had a few good moments, but the intellectual level of this debate was lower than the McCain-Obama encounter, and the use of English was definitely worse. A complete English sentence -- subject, verb, object, clauses in the right places -- was a rather rare commodity in this debate. Palin at times sounds to me like a non-native speaker, or more specifically someone who has not grown up with the language. Admittedly, this may have something to do with regional differences: English is spoken differently in different parts of the country. Moreover, this reaction is not to meant to be snobbish or picky. I have no objection to her colloquialisms, and I don't really care deeply that she doesn't how to use the verb "to attribute." I just find it difficult to listen to her and, frankly, almost impossible to watch her (though I forced myself to do so a few times). Her efforts to channel Ronald Reagan will no doubt have greater appeal to some others, however, than they do to me.