Single vs Bi-wire Speaker Cable

I can only speak to my experience with bi-wired Vandersteens, and they recommend true bi-wire (not one cable set up with internally divided wiring)... TWO separate cables. They don't like using one cable with jumpers, if true bi-wire is available. FWIW.

I used to like two separate cables but when I tried some jumpers of the same quality as my speaker cables, I never looked back.

All the best,
Nonoise

I like to eliminate the biwire option from my speakers (although this precludes bi-amping which is a different question).  Then use one large gauge high quality cable.

I suspect most of the occasions where biwiring helped, the speaker cables were undersized.

Jerry

I’m also in the bi-wiring is a downgrade camp. The key is to use a good jumper and not the usual low quality ones that come with most speakers (which many compare bi-wiring against hence thinking it’s better).

I started with a good pair of speaker cables and matching jumpers. (K-S Elation).  Then I swapped out the jumpers for another pair of Elation cables.  
Sounded better.  This is apples to apples, not comparing a good cable with matching jumpers to two lower quality cables.  Start with the best cables you can afford with matching jumpers for sure.  You can always try adding the second pair later.   And I do feel keeping with the same cable brand and model if possible.