I surely miss the developer/tech atmosphere that was there in Berlin, Frankfurt, etc.
The life is quite simple, and the coffee culture is based around chatting with friends for hours, instead of sitting in a cafe and getting work done on a MacBook Pro or a Thinkpad X1 carbon.
If you live like a local, which is not to say any lower living standards, it can be pretty cheap. At around 2x the living cost of a local, one can live comfortably here. I pay around third the rent which was once near Berlin, and now spend about half on food if I eat out.
Internet is cheap but unreliable. I sometimes have to use my 4G mobile hotspot (1GB/day at ~€4 a month).
I was born and raised in an Asian country, so there isn't much of a culture difference to speak of. However, Vietnamese is pretty difficult to learn, and even after six months here, I still cannot get the tones right and speak more than 50 words. Indonesia in that regard is amazing.
If you are thinking to move to south East Asia, I can highly recommend Indonesia. They have countless mountains to climb, a good hiking/riding groups to easily join, similar living cost to Vietnam, and a much easier language to learn. Bahasa Indonesia is understood pretty much everywhere, and quite easy to learn. Internet is censored in both countries to some extent (Reddit doesn't work in Indonesia with a DNS blackhole that you can easily bypass), and has worse Internet in Indonesia in general though.
There are many startups based in Indonesia (such as Gojek, Traveloka, Tiket.com), some of which are owned by SoftBank a few layers up. I feel it's more easier to I best/startup in Indonesia too.