Well I watched the video all the way through and thoroughly enjoyed it, mainly because I use local contract assemblers over here in Blighty.
When I started my first production runs, I tried out China but the quality was awful, primarily because they substituted parts despite them insisting that they wouldn't do that. The culture is to say yes to everything, and then cut corners. They will say they will order the parts from Farnell/Mouser/Digikey/RS as per you BOM, but they won't. They used crappy voltage regulators, with a 25% failure rate, that dumped 5V onto a 1.2V bus, also busting the most expensive parts on the board in the process.
They even had the nerve to complain that the connectors didn't fit the board because they'd not ordered the ones I'd specified. (An interesting aside to this is that I warned the Raspberry Pi folks about exactly this behaviour in China, and look what happened to them when their assembler took it upon themselves to substitute RJ45 jacks without magnetics and they had to have 10k+ boards reworked as a result).
My first run China run had a 50% fail rate due to their parts substitution. The straw that broke the camel's back was that China shuts down for two weeks during the Chinese new year. When you're looking at your cash flow, and you won't see any boards for at least six weeks, it's time to consider other options.
Yes China is cheap, maybe half the cost of a local assembler, but you will pay for it in other ways particularly in low to medium sized runs. If you can afford to have someone you trust working for you in China who will manage the vendor relationship and who understands the culture, and can physically manage the vendor, then it can work. But otherwise I strongly recommend, from my own experiences, that you find a local, personally recommended, assembler where you can look into the whites of their eyes, press the flesh, and have a proper business relationship with.
A local manufacturer works better in other ways too, not least that if something isn't right you can jump in your car and resolve the situation, or more frequently organise for parts for quick delivery when the P&P machine goes tits up and sprays the atmosphere with 1,000 unmarked 0402s. You're buggered on that score if your assembler is in China.
What I've highlighted here is that it's not at all rare for small to medium scale assembly to take place outside of SE Asia, in fact I'd say it's probably the norm.
Make sure any assembler you use is capable of placing your parts. One I tried had a 4 week contracted turnaround, then returned the parts unassembled 4 weeks later saying they couldn't do it because 0402 wouldn't work in their machine. They said they could do it, but failed. That really pissed me off as you can imagine, another cash flow nightmare as well as a bunch of irritated customers. I ended up hand placing that entire run myself, 12,000 parts in total.
One final point I'd like to make is that a personally recommended assembler in my experience turned out to be significantly cheaper and more flexible to the assemblers that you find on the internet where you plug in the number of componenents and how many BGAs or fine pitch devices you have.
So don't be surprised that there's manufacturing going on outside China, it's much more common than you might think.