I must say that I do like the Gator cover. It is VERY stretchy, black and the feel of it is beautifully soft. I also believe it will wear well with care and will probably also launder very well. All in all I am satisfied with the cover.
However, on first trying to fit the cover I did have some difficulty. The secret is in pulling the cord tighter BEFORE trying to put it on the keyboard. Otherwise it will just "ping" off - it is that stretchy.
With the cord tightened, the cover now stretches over the piano and I make sure that the cover also goes over the X-frame supports on either side of the stand to keep the cover in place. In fact I think it would probably be a better fit if I tightened the cord a bit more. But so far I have not done so.
I am not sure if this cover would keep out all the dust if the piano was kept in storage for any length of time as this cover seems quite thin, but since most people use their pianos on a regular basis this should not present a problem.
All things considered, this is a good buy and it even stretches sufficiently to also cover the instrument's sheet music holder.
It takes some getting used to, but I believe it is a 'keeper'. It does the job.