I have the Macbook Pro 16" (2021) model, and bought the Space Gray keyboard cover.
The Good: The color is really pretty, and gives the Macbook a little personality while still leaving the keys a neutral color tone that doesn't distract too much from working. The silicone matches up perfectly to the keys and has been extremely easy to put on and take off - there's no residue or anything like you would get with a sticker. The cover absolutely does what it's supposed to, and protects against crumbs or accidental drink spillage. The item was also packed well and you can tell the seller cares about making sure people get top quality!
The Bad: I find the symbols and words don't all match up. The "command" word and symbol are way off to the side so don't line up at all, and the icons used for the FN keys are different than those used on the Macbook itself in some instances in addition to being completely offset. I'm not sure if it's a printing error or if the Macbook model using the same keyboard size is just using different icons/placement and this was made more for that one than what I have. Anyway, this is pretty noticeable to me when the keyboard backlight is on, which is amusing because for the ones that do match up well (all the letters), I can't really see the backlight much. Thankfully I don't look at the non-letter keys often, and I don't use this laptop in the dark, so this doesn't bother me too much.
The Neutral: It takes some time to get used to typing with the cover on if you're not accustomed to doing so (this was my first ever keyboard cover). I still make some typing errors when I'm going fast, and I don't like typing on the silicone as much as I do on the keyboard by itself, but that's a personal preference - some may prefer the feel of the cover. It doesn't hinder me at all, and the cover is quite thin, so you don't need to relearn too much to use it.
For my purposes, I'm pleased with it. This is my work laptop and I would strongly prefer to not accidentally spill coffee on it or get crumbs wedged between the keys (I'm very clumsy and it's already saved me once in the couple weeks I've had it). I could definitely see buying another cover to switch back and forth depending on your mood!
