I no longer have the QB2 loaner, so I really can't add much. The Soundmagic E10 has a bit more of a V shape compared to the QB2, so that's going to make the QB2 a more neutral sig in direct comparison. The QB2 sounds a bit softer in bass note too, so while it has a little less bass, it's not quite as defined as the E10 bass.
The bass is really where the biggest differences appear. Both have fun, sparkly treble with very good timbre. The E10 has a bit bigger staging, due to the pushed back mids.
Both have cables I'm not exactly fond of. The E10 cable is stiff and springy but thin and manageable. The QB2 is a thinner flat cable, which still tangles but is more manageable than thicker flat cables. If you wear over the ear, neither will have microphonics issues. I don't wear iems down, so I don't know which will be worse that way. I can say that the E10 cable is durable. I use it to do yard work regularly and have never had issues. I'm guessing the QB2 to be as durable though. When I'm mowing or using a motorized tool, the extra little bit of bass sounds nice (I use other hearing protection cups over my ears and iems to be able to keep the volume low/reasonable).
I'm very fond of the E10 and like it more but that's just personal preference. I really like the QB2 as well.