I take this route as well because my typical commute is at 8:15am into Uptown (Duquesne) and then back to Oakland around 4:15. The Forbes Ave. route is so dangerous at that time because 1. Cars haul ass up the 376 off ramp, 2. Theres no easily accessible was to get into that old lane that is now a car free path 3. There are no cut outs at the end of that bik free path to allow easy access to the sidewalk for someone on a bicycle. Its especially hard when you wear clipped in shoes to unclip and hop up the curb before a car comes barreling up 376.
I've never had a bus come up behind me while taking the 5th Ave bus lane and if I did I would quickly jump on the sidewalk so as not to cause a delay. I've also never got any strange/mean looks or threatening words or gestures from motorists. I will continue to do it because it is IMO the quickest, easiest, and safest route from Uptown to Oakland without going all the way around to the Jail Trail.
That hill, as easy as it is, sucks so much ass though when you've got a backpack on that weighs about 25lbs.