Reply to Benefits of using Kontrol X1s with Kontrol S4?

I currently use only a Kontrol S4 for all my DJ needs. I've seen a lot of people combining it with the X1 and I am curious if you guys could elaborate on what you believe are the best benefits of adding one or two X1s. Of course, there's the huge advantage of not having to switch the decks of the S4 between A/C and B/C for playback controls, but there still aren't any jog wheels on the X1s. What do you find it most useful for?

There's also the new F1 coming out which seems like a great addition to control the remix decks.