I'm not 100% sure on which aspects you are exactly talking about regarding setting up a business. I don't know if you just mean making money online and living in another country or something more, so I will take a guess at a bit of both...
Some friends of mine have chosen Vietnam to set this pretty much up and speak highly of it for their digital marketing needs.
They seem a bit locked in to that country now probably due to setting up all aspects of the business there and now living their permanently pretty much, but they have many personal ties with the country which I'm sure made it easier.
However another group of friends who I would assume are probably on this forum somewhere have taken a more nomadic approach and set up what they can in Thailand then other more important parts in their home country, spending a large portion of the year in Thailand ensuring the business is running and all that jazz and able to leave it self sustaining for a portion of time to recheck the other aspects back in the UK. These guys had a lot of problems setting any real things up in Thailand and didn't recommend it for actual business related things, only living and working on the internet from kinda place. Rent costs are low for them and they find it very nice to live in, and they can get cheap workers for their needs, but they have admin problems and find lower quality in a lot of other areas.
If you are talking about setting up elements of business such as registering a company, getting an office, workers, admin kind of stuff, well I have NOT BEEN recommended South east Asia for any of these elements personally.
Specially if you don't know more about the country.
Pretty much everyone I know in those parts of the world have followed the same pattern, register the company and all that admin and tax stuff somewhere else, and then live in those places and work on their business online from there, I would guess that is no coincidence.