Drone vs. Helicopter
Both have their places. Generally drone work is under 400ft. and helicopter work is over 400ft. However there is a bit more to it than that.
Drones are better for small projects/sites and can get lower and closer than helicopters. That makes them the choice for homes, constructions sites, condos, yachts, and other properties. Drones are also much better for twilight photos. Drone work is also less expensive. I am a FAA 107 licensed and insured drone pilot.
Helicopters are the choice for anything that needs a higher or wider view. If you need to see how a property relates to areas around it, or want to drop a rendering into the photo, a helicopter is probably the right pick. There are also places a drone can not fly due to regulations or distance from take off spot.
I have been doing this for a long time and can advise you on which is best for you needs.