my thought on the subject is to have your site on all search engines. that way you get clients from everywhere. but google is definately good to be indexed with them.
Those results should come as no surprise as Google is the most used search engine in the world. I only get good results from Yahoo on one of my sites for some reason.
Not all users use Google, and in fact I find it faster to get started and high ranked with MSN, but you shouldn't ignore Google as it is a huge base of potential users.
I agree that MSN is easier to get listed with but that is because it is easy to spam your way into the top of the MSN results. Google is still by far the most used search engine in the world.
But have you looked at conversion. My google users hit and avergae of 1.5 pages, not normally getting to point of sale. The MSNer hit an average of 5, normally including a point of sale.
I actually get more hits to the point of sale from MSN though it is less than 5% of incoming hits.