I like the fluidity of the search tool and the fact that "search history" is listed in the sidebar

Just searched my top keyword for my website and found myself listed #2 in the first page of listings so I'm content with that! lol
It kind of reminds me of the search conglomerate engine that's now set up at Leapfish.com, though their advertising program offers 1 time payment for life rights to the top spots for your keywords, which I think is a mistake, but it is what it is...
Admittedly have not checked out the MSN ppc program, but I think competition is certainly good. Maybe it will drive cost per click down on google a bit!

I am certain that google ppc enthusiasts will still continue to use google, but this gives them another avenue for expansion and gives hope to the "little guy" that he can at least gets his feet wet in a lower cost ppc option before taking on the Google giant.