It’s designed specifically to take public transit. It also uses your location data when on a bus/train to let other people know if there are delays.
During route planning you see the type of transit and what your connections look like. It also tells you when the next bus/train is arriving. Knowing the next bus is 10mins away vs 45mins is important.
I've been using Transit to get around the DC Metro area for a few years now. It's pretty damn helpful and reliable. Sometimes they're not accurate (buses don't show up in their system, or are in the system, but never show at the stop) but I expect that with public transit.
Either way, it's the best app I've found (for this area at least).