Comparing it to dedicated synths, costing almost as much or more for just one sound is not really fair. It can sound good and out of other grooveboxes IMO only Push 3 has objectively better synths, which costs 2.5x as much. It’s also possible to route audio to external fx - I use DT for reverb and delay, which really aren’t that great on 707 (but not terrible either - they’re usable).

For me, major PITA of MC-707 is that 8 tracks are shared between internal sounds and external MIDI and have fixed midi channels (you can change them in settings, but sadly not per clip/scene, not even per project). DT is much more flexible in this respect with it’s dedicated midi tracks and midi channels per pattern. On the other hand, DT is very limited in effects department, which is where 707 shines and that makes them really cool combo.

Btw., I always set sound levels to be correct with all faders fully up and only use them for fade in/out and attenuate sounds while jamming (if for example tweaking something like resonance makes them too loud).