I compared the sound of both in-store but not side by side, for what that's worth.
Initially, I bought the JBL Bar 3.1 and kept it for 1 day. To me, the sound was somewhat muddy and vocals sounded like someone had a hand in front of their mouth. So off I went again, and once again listened to a bunch of bars in store. Ended up taking home the Q70 based on the sound first, and nice sale price second. In our small living room it sounds pretty good, and dialogue is pretty dang clear. Not perfect, but this is a soundbar with tiny speakers in an open space. Subwoofer is sufficient unless you're looking for earth-shaking bass.
**Edit: Add to this I am not a Samsung fan, and actually was hoping that another brand would fulfill my audio needs for this particular space hence the JBL purchase/return. I'm just not into the whole Samsung eco-system or any of them for that matter.