Duelund was never part of Jensen before or now, they used to get some of the manufacturing process done by Jensen under contract, then Jensen closed their capacitor manufacturing arm and Duelund bought a lot of the machinery Jensen no longer needed.
Duelund have always had the CAST line which is more transparent than the VSF capacitors, most notably in the highs.
The VSF have a warmer richer lower and mid character than the CAST.
Edit: the VSF are still available, they will make them for special order, so that means larger orders, and they are pretty pricey.