Welcome to the Kindle dark side, babyd.
I ordered the lighted cover, too. I was concerned with the light coverage and added weight/bulk, but I'm not the least bit worried about the hinge lock.
I have Amazon's cover for my K2, and I've never had an issue with it. I think the people who had problems fall into two categories: Those who tried to force the case to open from the back, and those who used brute force to remove the Kindle from the case, instead of releasing the spring clasp.
The instructions that come with it are simple to follow. Just remember, if the case resists, you're doing it wrong.