Simply put MSN returns MUCH better results these days if you compare it to Google over a wide range of subjects and terms. It has a little more spam but that is more than offset by MSN's far superior relevance.
Google's witchhunt on all things SEO will be it's death as far too many relevant sites get caught up in it (not to mention that many heavily SEO'd sites are also very, very relevant).
Eventually the public will realise too unless Google starts to improve or MSN goes the Google route. The only problem is that 'eventually' is the keyword.
