I've this same experience

I use my hotmail address for webforms where I don't trust the company in question not to sell my address down the river (most of them...) so I'm not surprised that 95% of the email that makes it to my hotmail inbox (after the spam filters and some custom filters) is spam. But I've also noticed quite a few legit emails going to the spam folder, and some not even arriving there. It's quite aggravating. Gmail and yahoo don't give me this kind of problem, although admittedly the spam volume going to those addresses is much smaller in the first place.