I can buy a drone in US or Canada like the DJI Pro 2 for over 1000$. But when I search professional drones on Ali they advertise many that share many features such as 4K video, dual camera, 20minute flying time. The one main thing I don’t see on many drones on Ali is the long range ability which DJI has. Is that really what I’m paying for with DJI, the range? It would be great if someone here has bought a drone from Ali and can lend some advice. And if you know of any decent Ali brands of drones please recommend.
It's relatively easy (for you or a factory in China) to buy a set of components and put together a drone, but just looking at the raw specs doesn't tell you the whole story.
For a start there are some very cheap 4k cameras, with poor dynamic range, colour balance and low-light performance. Image quality is quite hard to quantify, and even if they do give you any figures, they are hard for a beginner to understand.
DJI drones have a set of sensors to detect obstacles and prevent you flying into them. Cheaper drones generally don't, but even if they can claim more sensors that doesn't necessarily translate into better obstacle avoidance.
Then there are various software modes, usually with fancy but not very descriptive names. These may be really useful for whatever sort of video you plan to take, or you may never use them. There's no kind of industry standard so it's hard to tell if it's just a gimmick.
In this sort of market, where there's one big established make, there may be a small, innovative company with a superior product at a lower price that is struggling to be noticed - but there are also a lot of copycats who will throw together the cheapest possible thing that will look the same on the advert (and with no after-sales support).
Be careful not to "judge a book by it's cover" - look for reviews and instructional videos, and try to work out which are just thinly disguised adverts. See if there's a big fan/user forum, and if the manufacturer ever answers their questions. Or just buy a popular product that you can see works well for lots of people.