Besides being a hobby photographer, David is a tech writer and founder of drone buying recommendations site: https://www.dronesbuy.net
If you're looking to get good quality 4K video, you're better off spending some more money on a good DJI drone.
There's a reason why DJI have picked up 70% of the drone business - they make good drones. And we've seen how popular such drones as the Phantom, the Mavic and the Spark have become.
It's simple - excellent drones, with excellent video capability.
Do you have to pay a premium for these drones? For sure. But you know you're getting quality stuff.
If you're looking for recommendations, we at https://www.dronesbuy.net have performed a full analysis and roundups of plenty of different drones for specific reasons, including drones for video.