I like that live.com is easier to type: one character less than start.com, and a lot easier than typing search.msn.com (and also easier than google.com!). So I am not using start.com as the choice for a quick search portal. Of course, first thing I do after getting to live.com on a random computer is to hide the sidebar, etc. Although, to be fair, clicking on "hide" consumes one more click.
On the other side, starting today, live.com replaces start.com as my home page on all my computers... 🙂
What I also like: the search results now look a lot more closely to the MSN search results. My main problem with start.com was the way search results looked like: no "cached page" link, and a lot shorter text summary for each link.