Since I haven't commuted to my current workplace yet and I'm unsure if I ever will, I'll comment on my former 20mile one way commute.

Pro:
Wide shoulder 80% of the route.
Ability to use rail trail, although I only used it 1 out of every 5 commutes.
Only one steep hill. Lots of rolling hills which made me a stronger rider!
Low traffic in the morning

Con:
Narrow, broken pavement 20% of the route.
Speed limit 55 mph, although cars insist on doing 70
One segment was high prone to flooding/mudslides which would result in taking a detour up & down a mountain road
Not having that job anymore so I no longer have that route