I have only the Digitakt and use it a lot with my DAW through Overbridge. The DAW makes a greats sound source for the Digitakt, but the Digitakt I also use as both a sequencer and midi controller for the DAW, allowing me to sequence VSTs and control parameters via CC using parameter locks.
Overbridge VST allows be to capture all the audio channels from the Digitakt as well as all the MIDI, so I can capture sessions and edit out or embellish all the mistakes later. They make great combo giving me 16 audio channels controlled by the Digitakt.
That said I do intend to add an OT at some stage, but having used DT + OB I am not in any rush.