The Vice-Presidential Debate

Actually this is not on the vice-presidential debate last night. I haven't watched it. However, I have seen some news articles on it. Therefore, "on media responses to the debate" might be the proper term. It seems to have been very intensive and exciting unlike the presidential debate. However, this is not really for the debate but for the sampled data analysis.
Some say Biden won (CBS, 50 to 31) but some other say Ryan won (CNN, 48-44). Still we'll have to wait until Monday the debate result is taken into account and opinion polls adjusts accordingly. However, other media than CBS and CNN are saying Biden won because the CBS poll shows much greater margin in favour of Biden than the CNN poll. I was not sure this was a proper way to analyze the data in the first place. However, there may be some other better reasons why we can believe so.
CNN conducted survey on 381 registered voters who watched the debate (http://politicalticker.blogs.cnn.com/2012/10/11/cnn-poll-on-debate-winner-ryan-48-biden-44/comment-page-183/); CBS collected data from 431 uncommitted voters. According to CBS, an uncommitted voter is defined a person "who [doesn't] yet know who [he or she] will vote for, or who [has] chosen a candidate but may still change their minds."(http://m.cbsnews.com/fullstory.rbml?catid=57531059&feed_id=null&videofeed=null) Obviously, there is some gap between the CNN poll and the CBS one. The former seems to be more random than the latter. The latter's sample seems to represents only swing voters's opinion. Therefore, we may conclude the CBS survey is biased, and CNN's survey is better. However, is it?
Since this election campaign is a neck-to-neck race, the margin between the two is very narrow. Neither Romney nor Obama is the sure one. They are fighting within the error range. Therefore, the lead in the CBS's sample is a bigger deal than in the CNN's one. Of course, I will have to say I will wait till Monday a better conclusion can be made.