What there does seem to be almost universal agreement on is that the Tories are outperforming the national swing in the marginals. Indeed, a lead of about three points in the polls should make the Tories the largest party in a hung parliament. Labour think that if the Tories are six points ahead they will win an overall majority, while CCHQ believes it needs a seven point national advantage to guarantee a majority.
One thing it would be good to see more polling on, is the Tory Lib Dem marginals. There are 24 Lib Dem seats in the top 120 Tory targets. My understanding is that the Tories are only confident of winning about half of these. But then, oddly enough, a stronger Labour performance should help the Tories in some of these seats.
PS UK Polling Report is absolutely invaluable when it comes to trying to understand the poll, what is a significant shift and what is not.