It's a solid, well made mat. The founder of 321 STRONG seems to be very interested in making sure everything is good with the product, that there are no problems. Absolutely no problems here.

Fit as advertised. As of this writing, the screen is still scratch free.

Before installing the product, I watched their YouTube video (found by searching as instructed on the inside of the package). Applied it as shown, and it went on perfectly. No dust, no bubbles stuck underneath. My previous experiences applying screen protectors has often left dust underneath, no matter what I've tried, but this one went on well.

So far so good. It was easy step by step installation process. Fit great on my phone. Great product over all.

I bought another screen protector from this company for my previous phone, a Samsung Galaxy J36. When I got my new phone, the Samsung Galaxy J3 2017, I tried using one of the screen protectors for my old phone for my new phone. The problem is when Samsung redesigned the J3, they made the new model ever so slightly smaller than the previous model, which meant the screen protector didn't quite fit. Not LK's fault at all, it was just not made for that phone. Oh well...

As far as this screen protector goes, it seems to fit my phone just fine. All the cutouts are in the right place. The protector itself is cut so it doesn't quite extend all the way to the edges of your phone (though it does cover the whole screen itself). This is done so you can still fit your phone in an aftermarket phone case. I don't know about the oleophobic coating, my screen still has smudges all over it, but I mean that's just to be expected.
I am only giving this 4 stars because the first time I tried to install this, when I tried to pull off the backing to expose the adhesive side, the pull tab just popped off, leaving the backing on. I was unable to remove the backing without this, which meant I had to use the second screen protector this came with (there are 2 in each unit). Maybe that's why they include 2 in each box? But I was able to install the second one without any problems.

A few pointers:
The screen on your phone must be COMPLETELY clean before you install the screen protector. Even the slightest little bit of oil or dust speck will get trapped under the screen protector and stay there forever. The kit does include some wet and dry wipes to help with that, but I recommend using a microfiber cloth and some glass or lens cleaner prior to beginning the installation process.

Once you've lined up the screen protector with your screen, I think it's a little easier to use the stickers to form a hinge lengthwise, rather than at the bottom of your phone. Or at least that's my experience. YMMV.

Once you peel off the backing and stick the screen protector on, it's best to start at one side of the screen and work your way to the other to work out the air bubbles. If you do get one stuck under the screen (like I always do) it's not a big deal; it'll work out after a few days of normal use.