I changed from Yahoo mail to Gmail because of that feature!
There are emails I get which are not spam, but are still a nuissance...like articles from magazines or societies or comments from my wiki or all those forwarded jokes from my aunt and so on. Having a quick way to set up filters for these sources is an ENORMOUS help. You'd have to include this feature if you want me to consider leaving gmail.
I can not emphasize this enough. If it came down to Google versus Zoho, I'd chose Google because of this one feature.
Good Luck,
r_gutowski