Can’t say anything about modular gear but I’m using the Digitone for exactly this use case and it’s great! Apart from this: Digitone key filter modwheel and pitchbend of external midi controller
Overall I think it’s the better alternative: You’ll get polyphony and with the filter, it can sound a bit analog 
But you have to like the sound characteric of the Digitone. I ended up keeping the Digitone for all its great things and now added a Behringer Deepmind as a real analog polysynth…