FWIW, I've only had my K3 for a few weeks... but I've gone through 2 cases and 2 lights... and have returned them all for the lighted Kindle cover.
Both cases that I tried were very well made and did the job. But my complaint was that the way the K3 fit into the cases caused a problem for me getting to the right arrow bar. Any case made this way could/may have the same issue and both my cases (from different mfgs) had the same issue. Here's a pic to show what I mean:
Maybe my thumb is too big. But I always had to be careful hitting that right arrow bar because the case material intruded just enough to be in the way.
And the light issue: I bought the Pathway light from Target and the Mighty Bright TravelFlex... and returned them both. The Pathway was too large and clunky for my tastes and I couldn't even close the case cover with it on. It was always an issue of putting on and taking off the light. I just don't want to dink around with a bunch of gear (I take my K3 all over the place with me).
The TravelFlex could have worked, but recognizing that I was going to replace both cases anyway, I figured I might as well get a case that provided no intrusions on the face and had a light, all in one package. And while I don't often need a light, those few times when I do it sure would be nice to have it available if I remember to bring the light along. With it built into the cover like the lighted Kindle cover, I have it all in one nice and neat package.
So the lighted Kindle cover is now on its way to me.