HP Folio ultrabook versus Macbook Air?

I?ve never used a Mac computer and I?ve honestly never been that attracted to them, but everybody agrees that they are better than PCs.

I am a person who uses his computer primarily for web browsing, downloading music and messing around with Microsoft Office but every now and then I tackle some very heavy Excel worksheets from work or PowerPoint presentations with heavy HD images. I realize I don?t need the super-duper graphics from a Mac but the fact that they are (almost) virus-free and that they have a longer life-span than the rest of computers make me consider them...

On these basis, what would you think is best, a 13.3" HP Folio ultrabook or an 11" Macbook Air?
(I actually prefer the smaller size because it makes it more practical).