I was skeptical about a slipcover but am I ever glad I bought this.
Once I figured out how to get it on the couch and stretched, tucked, and tugged it into perfect place, the couch looked AMAZING. I am shocked at how good this looks! 
And it stays in place! It's been on a week and I haven't had to do any retucking, tugging, or repositioning. The couch is our primary sitting spot and so it sees a lot of action- and this slipcover is up to the task! I am so glad I bought this. It's like getting a new couch for a fraction of the cost.
The light gray has a bit of a purple undertone to it. Just as a note on the color.