Airbrushes, in general, will all do the same thing and that is to lay a coat of liquid material on an object. Most airbrushes properly maintained do this well.
Spray cans and airbrushes do the same thing; they spray paint. But an airbrush can spray finer, nicer, and easier with more refinement than a clumsy spray can.
Airbrushes quality and feel is subjective and is a learning experience. Some people prefer Chevy over Ford and some like Hondas and Toyotas. Some people like all-meat versus combo pizzas. People can and do argue the virtues of owning a Nikon or Canon camera. And some people like an Iwata over Badger or Thayer & Chandler. It is all subjective with no concrete answer.
It is all debatable but in order to debate the best airbrush argument shouldn’t a debater try all airbrushes in question before arguing the merits of airbrushes?
That said I will add I prefer the Iwata over Badgers and Thayer & Chandler airbrushes. I’m from reverse learning. I started with and bought one of the first Iwata airbrushes in this country in 1983 when all the artists used Paasche airbrushes. I still use that Iwata HP-C. Now I use, along with the HP-C, an HP-A and HP-CR. I also have a Badger 100sg, Thayer & Chandler Vega Nailaire and Omni 4000 to play with. I tried the other brands because I wanted to see what if they were better for me. I really tried and I finally went back to the Iwata airbrush because of the extra quality the company gives.
The Iwata airbrush feel is subjective but this is my opinion. The finish on it is of higher quality. The chrome plating is nice and heavy, and is slicker than the others. They have less slack and tighter manufacturing control for a more reassuring feel to the operating mechanism. It is simply smoother operating. The paint cups are smoother and easier to wipe clean. The balance feels better and I don’t mind handling it all day. The parts, while initially more expensive, are of better quality and do not wear out as my 21 year old HP-C will verify. As an example people complain about an Iwata needle costing more but they do not realize that the needle is made from a far more durable and costlier to make stainless steel. If you have to replace a less durable needle in another company’s airbrush then in the long run the cheaper airbrush part costs more. The Iwata will last and perform longer and better for a longer time. I’ve never had to replace a part on my ancient HP-C and I’ve sprayed gallons of everything except pesticide through it.
It reminds me of people driving cars. You can buy American quality with less durable, cheaper and more frequently replaced parts or buy foreign parts that cost more, perform better and last longer. I prefer long lasting performance rather than mediocre airbrushes. What do you want to drive? A Lumina, Taurus or Camry? Cars might have the advantage in that you can test drive them before you pay money. People cannot “test drive” airbrushes before they buy them.
Let me reverse a declaration on this thread: Send that poor Iwata over here and I'll show you that it can hold it's own against any American airbrush.