Most "Slipcovered" sofas from manufacturers are not designed to pull the cover off and wash it, if that is what you are thinking you will find that's not really going to work. They are tightly tailored to the piece and they can also shrink if washed. Performance fabrics are soap and water cleanable - so they have the advantage vs slipcover. They will not necessarily last longer, however. Durability is determined by the rub count of the specific fabric.

We have the same question. We are considering Crypton vs a heavy duty machine washable cotton for our sofa. Can I ask what you chose and how it went?