At the time I loved the Wal tone and preferred it hands down. Looking back, I think if I had to chose between which of the two to hear for a whole Rush show it would be the 'Berger.
The Wal was used from Power Windows through part of Roll the Bones to great effect. It was a very appropriate tone that fit the "hi-fi" sound of those records. In reading interviews Geddy explained how he chose the tone, and strung it with really light rotosound funk masters (.030-.090) to stay more in the mids away from the lows of the keys. I cannot imagine any other bass being used on Power Windows or Hold Your Fire (especially HYF).
That said, Rush is a rock band and the 'Berger is a rock bass, thus much better suited for their typical set list.
Of course, Geddy's Wal sound is one small trick that the Wal can perform, so I am writing this under the assumption that we are comparing GEDDY's Berger tone to GEDDY's Wal tone.
Overall, I think a Wal can do much more than Ged was doing which was maxing out the hyper-active funk tone. If I were asked to play a Rush show I would bring a Wal.
), this development surprised me very much. But there it is. That Wal makes me want to squeal like a Belieber. So, I can identify a bit with your indefensibility. 
