I used to use the physical version but I found it took up too much desk space for the maximum buttons version I felt I needed. I’ve literally just discovered the iphone version which I am currently setting up. I opted for the paid version which gives an unlimited number of screens with up to 8 x 8 buttons on each screen but I find an 8 x 5 layout to be perfect. This is what one of my screens currently looks like although it will change a lot in the next few days. The nice thing is you can have screens with retro buttons and a duplicate screens with 2024 buttons.
The permutations are literally limitless. I prefer the iPhone version to the physical version I gave away which cost me over £200 
It works great with this sexy 3 in one charger:
