I confess I ordered this controller because of the motorized jog wheels feature. The first unit I got, clearly had a left jog wheel issue that caused the music on Deck A (and C) to drag and skip on its own. Got a second unit from Thomann and this unit is now working fine (thank you, Thomann). The motorized jog wheels in TT mode are a lot of fun to DJ with, no doubt. I'm a bit old school and I love vinyl. The S4 MK3 allows me to have all the fun of vinyl without the hassle of having to carry heavy records in a trolley. However, the operation is not as smooth as you would expect from such an expensive controller. Playing using either TT or Jog mode, there are still few "bugs" that cause the software to sometimes not interpret the MIDI signal correctly and the Tempo glitches a bit making beatmatching not so accurate... A slight nudge of the jog wheel and the problem solves itself.
I think it might be a TSI problem... Maybe even a firmware problem. Not sure. I'll keep experimenting with TSI's and wait for another update.
One huge overlook from NI, in my opinion, is the lack of dust sleeves inside the faders. This made me anxious, so I improvised some external ones made of felt and mask tape. Although the faders are inverted and carbon protect, that doesn't mean that dust sleeves are obsolete... In fact, if there were dust sleeves, the faders would probably last even longer. Alas...
That said, the sound is amazing and very clear, the unit feels solid, although it's plastic, and, so far, I love playing with it.
Note: Mac Mojave users have to create a new account/user with admin permissions and download the S4 MK3 Firmware Update from the NI website using Safari to be able to update the controller firmware. Otherwise, it just won't work...