Some can't live without Aurora anymore ;) - they start their projects with MySQL(even thought they prefer Postgresql) to be Aurora compatible, just in case they need it.
The comparisons I could find didn't seem to be very favorable to Aurora (mainly that the claimed 5x improvement does not show up in the benchmarks)
We cut our costs by about 40% after the switch and saw about a 20% boost in speed. RAM usage was lower too.
One of the biggest savings is that you don't need multiAZ since your data is stored redundantly. You don't have to worry about failover because the restart time is < 1 minute anyway. The other thing is that I can stop having to keep an eye on disk usage (and paying for unused space) since it just grows as needed automatically.
The man hours alone that we used to put into actively watching and tuning that DB have just vanished as has almost the entire sysadmin burden. That project was already on MySQL too which made it an easy move too.
I wish they'd do something similar for PG too.