I am currently bi-wiring after single wiring with brass plates and with jumpers. Jumpers are definitely better than the brass plates, not for the distance, but for the quality of the connection. Think about it -- after buying quality speaker cable, why would you want to complete the connection with crappy brass plates? I've used the Dedicated Audio jumpers and Transparent Reference jumpers, with the Transparents coming out ahead.
As for bi-wiring, I've heard both sides. I think it is probably system and speaker dependent and I would agree that a single cable of superior quality would probably outdo much lesser quality bi-wiring. In my case, bi-wiring improved the sound significantly. I'm using an older top of the line MIT speaker cable for the highs and a much lesser MIT of the same vintage, but similar construction, for the lows.