You are right! Vietnam is an ideal destination to live as an expat!

Not until I had invaded some expat shelters in Vietnam (both online and offline) to invite them to join our business startup as freelancers, did I realize how huge the expat community in Vietnam is with more than 90.000 foreign nationals.  No matter where you are from, we are all calling Vietnam home. As having lived abroad as an expat, I am sure and proud to say “You are right! Vietnam is an ideal destination to live as a foreigner” (especially those who are online entrepreneurs/ freelancers).
Here is how show you that I am not biased at all:

1 – Internet in Vietnam is just like TGV in France
And yes, it's somehow free everywhere here!
When I was staying in Manila, I always got frustrated being asked to pay for using WIFI wherever I went. No matter where it is, CBTL or Starbucks (where you usually have to pay handsome money for a cup of coffee) or a normal coffee shop, you  are welcomed but not invited to use WIFI unless you are willing to pay extra.
In contrast, you can easily find a coffee shop/ restaurant... on the way (in Hanoi, Saigon or else where) as a stop-over to make use of their free wifi to reply e-mails, do some quick errands, check in facebook,...  If the shop is not too crowded, you can supposedly stream Youtube videos as well. Planning to be based in Vietnam for long, consider sign up for a 3G package for your phone (which should cost less than 5USD per month for fast-enough speed and data usage), and for a WIFI/ fixed Internet line at home (which should cost less than 20USD per month)! Not bad, isn't it?*
* Has the price range changed without me noticing of?

2 – Maze of coffee shops are awaiting!
For the past few months, I had been living in Malaysia as an expat. Since my tasks were mostly to be done online, I did need good Internet connection that got me quite much time to wander around, do some research on every single place in order to find out where I could take my time sipping a cup of tea or coffee and working on my laptop at the same time. Unfortunately, there were not many choices for me.
Returning to Vietnam, I myself have been amazed by a growing competitive market of coffee shops in Vietnam. They are all offering great cafe culture to both Vietnamese and expats. I find it so hard to pick up one that I sometimes rely on some local search such as Clingme or Foody (any other app to recommend to me?) to check out the places are surrounding me and choose which one to opt for. However, Foody website/ app are both in Vietnamese and expats may have nothing to do with that. So I recommend you to use Clingme, though it's only available on iOS and not yet (hopefully soon) to be download-able on Android.

3 - Living in Vietnam is just a part of saving process
Whether you are earning a fortune or have been struggling with bringing a bacon home every month in Vietnam, the fact is that expats' average salary is much more than what a local person can get. Yet, like other countries in Southeast Asia, Vietnam offers you good food with cheapest price ever. Where else in this world can you expect to spend less than 5USD every single normal meal?
Since you are an expat, you may be expected to pay more than a local person. However, fortunately this scene is avoidable as long as you are willing to walk a mile out of your expat community to shop/ dine in local supermarkets/ restaurants... Keep those words in mind “Cơm bụi/ Cơm bình dân” (Inexpensive meal with rice and food range to be picked) or “Quán bình dân” (Inexpensive restaurants), “Giảm giá” (Discount)...

If possible, please grab some basic Vietnamese and I can guarantee living in Vietnam can help you to save money.

4 - Transportation Nightmare? No way, believe me!
With millions of motorbike flowing to streets everyday, traffic in Vietnam is supposed to be the worst nightmare ever in expats' thought. Nevertheless, it's just easy for you to buy/ rent a motorbike (or even car) for your own convenience of moving around as a local.
Which is more terrible than traveling by a motorbike? Supposedly, it could be “stuck in some public transport where you may get robbed, stolen or... who knows”. In my case, the worse thing is that I could not find really convenient public transport (in Miri, Malaysia) or cheap way of moving around (it just does not happen in KL, Malaysia with KTM system which is as crowded as buses in Vietnam but whose price may be double or triple)
Another bright side of living in Vietnam as an expat is that Vietnamese businesses are paying more and more attention to expat community through equipping them with English versions of services they are offering, say, Uber (for those to share a taxi trip), Grab Taxi (for those who wanna use smart phone to order a cab themselves and earn points), Clingme (for those who are looking for ATM, Petrol Station, Parking...)...

*The article is being written while I am living abroad and envy those expats staying in Vietnam! Any comment is welcomed and appreciated!