I really liked it for the most part I only have a few criticisms:
-adding new buttons and rearranging the buttons is a pain in the butt. Each button is numbered and when you change them in BackOffice you only see each individual item instead of being able to view each page of buttons as a whole. So, you have to have your own list and know which spaces are already taken up and which ones are available for new items.
-the color scheme is a little difficult to see, there's no option to change colors of the theme or buttons and the font is pretty small as well.
These are minor issues if you have a simple menu that doesn't change often. All in all I would recommend it.
We're in our second month with SK and added the credit card swiper more recently. We like it, customers like it. Less paper and enough info on the back end to know what's going on. The new mobile app. gives you a running total for the day so you can see how things are going if you're not there.
You do need to plan your register carefully and keeping a separate spreadsheet of your quick codes is a good idea. Editing single items is easy. Redoing the entire register because you left something off and you need to reorder it all is time consuming.