I added a whole lot more than 19 tiles, once I learned how to add tiles. That part is not exactly intuitive. I also removed half the tiles MS put on there by default. There are some I'd like to turn off the animation and make smaller. (Netflix and Hulu got to double size, and Hulu puts the most useless, ugly pictures up.) I wish it were more customizable.
Even the tile layout won't act right. The way it organizes automatically is annoying. The first few tile are always 2 wide, at 9 instead of going to a 3X3 mode, it goes to a 2X4 +1 to the right mode. Adding a 10th makes it 2X4 +2 to the right on the first line, when I'd rather have it go to the second line. It's rather stupid.
Overall, I like the Win 8 interface, but there are still some problems with it. I'd put it on par with Win 7 for stability, usability, and performance, but Win 8 has better security. So, I'll stick with Win 8 for my main machine and my laptop. My HTPC is still Win 7 because it's easier with a touchpad. Win 8 with a touchpad and no touchscreen is terrible.