Fleece for Guinea Pigs?

I've been doing A LOT of research about guinea pigs and I have decided to get 2 and build them a C & C cage [ 15 sq feet ] and I've recently heard a lot about fleece as a bedding instead of regular bedding. What are the pros and cons for fleece and if it isn't good what other type of bedding is the best? Any additional info would be great!