To Bi-Wire or use Jumpers?

Short answer: it depends on your system AND improvements from bi-amping rather than bi-wiring is another different animal entirely.

NORDOST has a good succinct commentary:

http://www.nordost.com/downloads/NorseJumperinstructions.pdf

They also highlight that a shotgunned double run of quality cables with quality jumpers instead of bi-wires may be your best bet.... But take it for a test drive yourself.

CHORD has offered their two-bits worth in the same vein.... CHORD no longer makes dedicated bi-wires and also suggest that quality single runs with matched jumpers may be your better performers.

http://www.chord.co.uk/help-and-information/speaker-cable-guide/bi-wire-or-single-wire/

My own personal experiences:

a shotgunned double-run with matched shotgunned jumpers of high-end cables in the diagonal speaker hookup arrangement suggested by the NORDOST article beat all bi-wired contenders and pretenders in my system....hands down 

using the reverse method but will try the diagonal to see if it offers better sound...

How about thinking about it this way.  For a given $ sum, you can get two runs for bi-wiring or a better single run.  If you get short lengths of the same cable to link the terminals (see Wireworld, for instance), you get better cable and avoid manufacturer-supplied jumpers.

The entire speaker cable hookup scenario is system dependent, and there is no answer to your basic question. The best answer is from another poster on this forum. "Bi-wire may or may not make a difference, and if it makes a difference, it may or may not be better." Whatever you do, IMHO, it is best to keep things simple and consistent. If you bi-wire, then 2 separate runs of identical cable, avoiding a single cable with bi-wire connections. If you single wire, then short jumpers of the same cable as the main run, and try different connections at the speaker. Jumpers in place, then main to bottom, main to top, plus to bottom - negative to top, or plus to top - negative to bottom.

There's no one answer that will be correct for every application and speaker out there, but more often than not, the money spent on a single run and quality jumper will outperform two lesser sets of speaker cables. I'm very much in agreement with the Nordost article linked above.