Well Jim Bergantino is coming out with next month is the NV115 bass cabinet, would be the way to go.
OOPS!!!! Maybe it is called the NV158, anyways sorry.
I own a Dr. Bass 1580 [ported], and IMO it doesn't sound much like a sealed Bergantino NV215 at all.
That said, I see nothing wrong with buying a used Dr. Bass cab if you like the way they sound; just don't give any money directly to Marc Serio aka Dr. Bass.
If I remember correctly there seem to be a financial problem with Dr. Bass, I guess he wasn't filling orders for people, I think there is a thread about that here on Talkbass some where.