I own the DBA-02 MK I and th SM3 v1. The latter has an imbalance problem, that's why I bought the DBA-02 to replace them.
I'd say they are quite different. The SM3 has much more low end, and an emphasis on the lower mids, thus giving a much warmer sound. However, the bass is also quite slow in comparison. Some would say they have a more realistic decay. They are also more detailed. There is more micro detail. That is not to say that the DBA-02 is a slouch. They are very detailed as well.
Regarding treble energy, there is no contest: the SM3 has very recessed treble, where the DBA-02 has upfront, crystal clear treble. Midrange on the SM3 is warm and thick. On the DBA-02, it is more neutral.
Now I got used to the DBA, I find the SM3 very thick sounding (too much actually for my taste).
I prefer the DBA-02 sound signature, but the SM3 remains a good sounding IEM.
What I really love about the DBA-02 is the ease of use: I'm using simple flange tips, very easy to put in and isolation is great, as well as comfort. With the SM3, I had a hard time finding a good seal, and only one tip worked for me. It's a biflange sensorcom tip. It's much harder to insert and pull out.
So for everyday use, and commute, I MUCH prefer the DBA ergonomics.