To OP: It's still a good thread, thank you.
On 6-string guitar I liked both 4x12 sealed and 2x12 open. This is my first bass cab and my first that's ported, in the front, a 1x15.
To me, there's a transition in its voice, as I descend the E string for example, and the low E ends up sounding quite different. I don't mind that it sounds "open", as I said above; I do mind a little that it's inconsistent with the rest of the bass. To me, open is emotionally different from sealed and I need either one or the other (or both but at different times), so I'll have to try a sealed cab (or a driver suitable for this cab with the ports closed).
So, while knowing almost nothing - sorry - I did vote sealed.