I tried it once with two bi-wire cables on speakers with three terminals, and after playing around concluded it was best with the Monster on the highs and lows and both of the XLO's spades on the midrange. After a few months I got a pair of tri-wired Straightwire Crescendo's, and the result was so much better I concluded I'd been kidding myself. Strongly recommend a single cable in bi-wire configuration.
Biwire with diffrent brands?
I've been doing some speaker cable comparisons, and I find to get the best balance in my system with the cables I have on hand I am using a diffrent brand on the bass, than the mid/highs. I would be interested in comments from those who have had experience or actually wire their system this way.