Well when cyclists are killed on the road in Vancouver it's usually a big story which leads me to believe that it doesn't often happen without us hearing about it. Further more I have never heard of a cyclist being run over from behind by a bus on Broadway.
For an experienced bicycle commuter Broadway is a walk in the park. The bike routes on either side are just annoying stop and start bullshit.
Im not really sure how Broadway can be faster than 10th. There are more lights, and more cars on Broadway, meaning you are going to have to stop and start alot more than on 10th. They have removed many of the stop signs on 10th (anything that used to be a 4-way is now two way or a traffic circle), to make things more fluid for the bike route.
Even if Broadway were faster (which in my opinion it isnt), the number of vehicles you would annoy/enrage by just riding on it (when you and they both know there is a bike route two blocks away) is not worth the possible perceived 'faster' commute.