Just helping to answer some commonly asked questions from people who are new to multirotors/RC.
"KV" stands for 'RPM per volt'.
(and 'RPM' stands for Revolutions per minute, for those who aren't familiar with the term)
Lower KV == More torque, Lifting Power and Thrust
Higher KV == More Speed, Agility and Acrobatic ability
In general when designing your new Multirotor airplane, you start of with the "standard/default" KV motor which is a comfortable 1000KV. Then based on your requirements (sports quad? heavy lifter? fpv?) you refine your choices further.
Ideally, you want to be able to hover your multirotor at around 40-50% throttle. Insufficient thrust and your multirotor starts to lose maneuverability and your FC's autoleveling starts to resemble a fat lady playing with hoola hoops. Give it too much thrust and your rig will be underweight and overpowered, resulting in excessive vibrations. Making this terrible for any kind of video (FPV/AP). However, if you are flying a sport flyer/acrobatic quad via Line-of-Sight then being overpowered could be your goal... who DOESN'T want to fly a rocket?
If you were building a generic quad (ie. you just want something cheap that flies reasonably well), you can't go wrong with a motor close to 1000KV, this is also ideal for FPV rigs as you might like some speed and agility but can't give up too might thrust because FPV gear has a tendency to be heavy.
If you were building an Aerial Photography rig, your focus would be flight endurance (aka hover time), lifting power, thrust and stability. Pick a good low KV motor within your budget, the difference in price is usually because of better quality components and efficiency. Which directly translates into better flight endurance and more air time. Getting a bigger frame and adding more motors (Y6/Hexa/Octo) also help to give you greater stability in strong winds, which are really useful for reducing vibrations/jello and keeping your target in frame.
Lastly if you were building a sport flyer, go for something a little over 1000KV. A good target would be Quad configuration running on 1200KV motors. That will give you a good base to build a nippy little devil for speeding around Tampines Field at top speed while flipping, rolling and tearing up the skies. More motors increase stability (your ability to stay horizontal), reduce flight endurance and adds unnecessary weight (making it harder to do tricks) and that is not what you want. Low KV motors can also be very expensive... and are just wasted on a sport/fun flyer. Put your money where it counts!
I could probably write 500 pages on this subject but let's just keep this short and sweet so we don't drive all the newbies away!
Hope you enjoyed reading my guide and maybe this would come in handy when you decide on your next build!
p.s: ... secretly hopes this helps encourage more multirotor enthusiasts in singapore!