UAVs in general cost only a fraction of the total outlay of a flight operation. Because of the decreasing cost of UAVs, many new players can make their way into the industry of aerial survey.
However, having a low cost UAV should not be the priority for high value projects. As with any component of a larger structure, an assessment of value should take precedence over cost. This is especially true when considering the processing of data, licenses, time to mobilize and labor - all of which may rise if you deal with a low quality UAV.
In general, a low cost UAV does not mean that the project will cost less If you have invested in a high value LiDAR, the upfront costs of your UAV should be the last thing on your mind. If you filter your data collection capabilities through a UAV that does not have the potential to translate, you lose money, time and labor that ends up being money in the long run.
Respecting Your Payload
Your payload is only as good as its method of delivery. It does no good to tell a client, "Our system has the capacity for the precision you need - if only we had invested in a UAV with an automated flight option."
What is the final deliverable that you are responsible for? Is your setup fit-for-purpose? If your UAV cannot make it happen, then you have basically wasted your money, no matter how little you spent.
The best LiDAR systems are incredibly complex systems. Top platforms have invested a great deal in much more than the sensor. The workflow in a system that is good enough to map out dense or steep terrain has been meticulously coded to deliver precise data almost instantly. The positioning technologies usually give protections against vibrations and turbulence. These advantages become moot if your UAV cannot even hold a particular flight pattern or flies unreliably when it reaches the edge of its range.
The ability to control and manipulate your payload is incredibly important. Low cost UAVs simply do not have the same kind of precision that, say, a NOVAerial Procyon 800E would have under trying circumstances. Features like an independent tail rotor motor, flexible payload and a single stage main rotor belt drive greatly improve the reliability and security of your data.
Reliable Data
The best manual joystick pilot will not be able to match the surety of an Ardupilot autopilot flight pattern. This is especially true if your project requires you to have multiple drones in a fleet. Standardizing the workflow allows for specialization in your vehicle systems without losing precision - program your secure flight patterns from the beginning and spend your field time focused on the details that ensure a superior deliverable.
Individual motors for each rotor also increases the reliability of your LiDAR - this setup completely gets rid of the much less unreliable main rotor/tail rotor drive line in your cheap retail UAVs. The single stage main rotor belt drive in a high value UAV increases durability and reduces internal vibrations. The Procyon 800E specifically also has support for 3D printed plastic parts, an option that makes this UAV more durable than fiberglass drones.
Project Security
The ability to customize your drone for difficult projects or last minute changes is also important in securing your data. Mother Nature has a way of spoiling the best laid plans, and with a cheap UAV, the out-of-the-box plan is all you have.
A high value UAV gives you the capacity to customize functionality to the situation at hand. The ability to adjust your payload angle to deal with a last minute request, new terrain or weather conditions makes all the difference when your project throws you a curveball. There are no magic bullets when it comes to delivering a survey grade project - you usually need control over all of your magic bullets to bring the best results to the table.
In short, why limit your results? If your data capture system puts you in elite company, stay there with the UAV that you choose. If the upfront cost is higher, it will easily pay for itself in the quality of client and the increased volume of work you receive once word gets around about what you deliver.