The website is easy to use -- you choose your laptop make & model, and then it takes you to a page where there's a pictorial guide to telling which of a small number of manufacturers made your keyboard, so you can pick the same one to get your replacement key. This was all easy to use.
It took about a week to arrive. It arrived in a regular postal envelope. The keycap, the plastic clip thingy, and the little springy rubber cup were all folded up in what looked like part of a paper towel, which was taped to the invoice. I raised an eyebrow. Then again, you really don't need a padded envelope for something this small and flat. So, good on them for not wasting materials, I suppose.
The key installed easily and worked fine.
Conclusion: sure, these folks are fine, and not sketchy junk vendors.
NOTE: This review is of ReplacementLaptopKeyS.com. If you go to ReplacementLaptopKey.com, it redirects you to LaptopKey.com. I have not done business with LaptopKey.com, but it looks like they're pretty much the same -- and their "how to remove and reinstall keys" videos are better and easier to find by random googling.