Covers have been discussed many, many times here.
My personal opinion is that the official cover is worth it and the lighted one is worth the extra cost. It's very well done, has professional look, smells nice
, fits really well, the light is useful when reading in bed (it can double as a flashlight if necessary). It can protect your Kindle if it falls.
There were some reports of issues with non-lighted covers, but my unlighted cover didn't have any issues. Finally, I decided that I needed a lighted one so I upgraded. No issues with this one either.