I'm impressively cheap. Thus, when faced with the "shall we grab a cab or should we take this free shuttle?" question, I opted for the shuttle. We waited maybe 10 minutes for the shuttle, then took a winding ride through all the other dropoff points. Maybe another 15-20 min? Then we got dropped off at the Pacific Place back(?) entrance where it wasn't any problem to pop up the elevator and get to the Conrad lobby.

However, I generally travel with one medium sized Osprey or Arcteryx backpack, no "luggage" as in suitcases, etc. I was in no hurry, so time vs. money equation didn't matter. No kids or elderly with me.

So: if you have similar travel, then go for the shuttle. It's not horrible. If you have luggage, time concerns, or people that need convenience... cab it.