Ultimately, requirements will vary depending on project objectives, operator experience and budget. Unmanned Systems Source have detailed a number of factors that should be considered:
Fixed-wing UAVs are generally better suited for rural environments and are work horses for many commercial and scientific applications. Though they may not offer the manoeuvrability of a multi-rotor UAV, when it comes to flight times and coverage, fixed wing drones excel.
The use of multi-rotor UAVs has exploded in recent years in large part due to their affordability and ease of use. But multi-rotor advantages certainly extend beyond these two points.
Ultimately, the choice between a multi-rotor or fixed-wing UAV for a specific application depends on a variety of factors. Understanding the strengths and limitations of each vehicle goes a long way in helping inform your decision.
There are some additional interesting points. Admittedly a bit simplistic but adding it in so it is available to someone pondering this question.