As someone who has tested both side by side they both have their pros and cons.
The Zulus has better low light capability, better day time resolution
The Sytong / Falcon is stronger build (far lower return rate too). The Falcon has much greater depth of view requiring less focusing.
At night time they are pretty much same in regards to resolution.
The Zulus has a wide screen format display. The Falcon more a 4:3 ratio. The Zulus more natural with colours. The Falcon more vibrant. We found customers when first looking through both devices were more drawn to the Falcon. I like the tethered battery cap of the Falcon. I prefer the aesthetics and the operating system of the Zulus.
I think it’s ignorant to write off Falcon. I'm currently testing a prototype Falcon 640x512 50mm multispectral. Testing it alongside the Thermnight 335. The Falcon destroys the thermnight on the thermal channel. Possibly thinking unfair comparison, but the Falcon is similar or lower price so will be its competitor in the multispectral market.
In regards to the Falcon brand they have dropped the 384 sensor and will only be doing 256, 640 and 1280. They made this call as they have moved away from HIK sensors to their own allowing them to build 640 products for the same price as the 384's. It will be interesting to see how they are received in the UK.
A lot of manufacturers are now producing 640 at the same price as 384 sensors... My chinese friends have implied this will be apparent more and more now...the likes of Pard and DNT use HikMicro thermal sensors... only a few main players produce there own sensors, that being Pixfra, HikMicro, Guide and NocPix , the others use Chinese UNI sensors... Lynred are used by Pulsar.
As far as Sytong, I used to sell them, they were not as good as Pard, they had to be HEAVILY discounted to sell in the UK market, the displays were inferior in comparison to Pard, although they used VCSEL IR and copied the Pard designs.. Now rebranded to Falcon. They have no established focal point in the UK and if I wished to purchase tomorow I could, but I don't as there are better products, with UK bases now supplying directly and dealing with warranty in the UK.
Back to the thermal comment, your comparing a 384px 35mm lens thermal against a 640px 50mm lens thermal and it has a better image , so yes it will be better , but even if a lower price, they have mount everest to climb before they can sell in even meagre quantites here...
I've been doing this a long time and using these products first hand... yes there ok and work, they all do !!! If these were mind blowing good and better than the competition in the UK market, I would be shouting about it..but there just another bang average chinese clone....