There is also a lot of luck and timing involved. I have similar sites with similar content and similar keywords.
Some do well in MSN.
Some do better in Yahoo.
A few do Best Google.
Some sites take a year to get any traffic and/or ranking; I have had a few new sites to go from page rank 0 to Page Rank 4 in five weeks. Others that have had page rank 0 for 9 months.
My advice is to try about 10 sites on several different IPs and see what works.