Thats a great question, and the choise between brushless, or servo based gimbals ultimately depends on what you need. Although brushless gimbals are very popular right now I still think there is a place for some of the servo based gimbals. So I will outline some of the advantages and disadvantages of both to help you decide.
Servo Based Gimbals
- Cheaper than brushless gimbal - servos can cost more than certain brushless gimbal motors, but you dont usualy need a special controller/battery just for the gimbal
- Much lighter than equavalent brushless gimbal - servos are much lighter compared to a heavy brushless motor)
- Much easier to setup and use - most flight controllers support servo base gimbals directly. Brushless gimbals usualy require a separate control board (FY-G3 gimbal has one integrated with each motor).
- Much better stabilization - the speed and smoothness of brushless gimbals is unquestionably better than servo based gimbals. Some complex servo based gimbals that use gears and timing belts achieve good stabilisation, but they are still slower than direct drive brushless gimbals.
- Some ready to use brushless gimbals work right out of the box, so you dont need to spend any time balancing and setting it up which can sometimes take abit of time (see our guide here)
Overall I would suggest that you go for a brushless gimbal 9/10 times if you plan to shoot video as the stabilisation between the two is like night and day. However if you are primarily shooting photos then you can save some money and weight and rather go for a servo based gimbal. One of the important factors with multirotors as that every gram of weight you save will mean you can fly longer.
Hope that helps, if you have any other questions or comments let me know!