thier main service is not hosting anyway. I have heard many bad comments about yahoo hosting that's why i never tried it.
Never use it before as there are too much bad comments. Btw they really seems resell those host, they even can't control it.
i am using godaddy delux hosting from last 3 months and i can host all my domains in that one hosting. in this pereod i didn't see anytime it went down. i am pleased with overall service.
I've never tried Yahoo hosting but I use a host called My Ideal Host who are cheap and so far very reliable. I'm only hosting my personal portfolio but it's been good so far and they support the file types I need to use.
Out of couriosety did anyone useing them notice any changes in yahoo serps when you started with them or any lose after you droped them?
Maybe your websites are down today like a few months ago Dreamhost provides many goodies (1 click install for some scripts...) but they are really not 100% reliable ( http://www.dreamhoststatus.com )