Because my sofa had a big camel back, and I didn't want to tuck in my cushion, I bought a separate cushion cover. The sofa slipcover was easy to put on as well as the cushion slipcover. However, the slipcover was a tad darker even though I ordered the same color grey which I didn't like, but overall, I am happy that I bought it as I don't have to worry about keeping the seat tucked in as it works wonderfully. 

(Back pillows will have to do until I get the sofa reupholstered this year as they will then match the chairs across from them that were done a few months ago. )