I am writing a review about a "visa on arrival" service called myvietnamvisa.com. There was a thread about it earlier on TripAdvisor that closed due to inactivity. One of the questions on the thread was whether the website is a scam. I would like to share my experience - which is that MyVietnamVisa.com is unequivocally not a scam.
First, MyVietnamVisa was extremely prompt, responsive to my questions, and professional in every respect. My wife and I had planned a trip to Vietnam and ordered a letter through MyVietnamVisa, and were extremely happy with the customer service. Steve, a customer service rep at the website, helped us understand the issues with the approval letters and instilled confidence in us that the letter would be accepted in Hanoi. Steve was flexible and prompt, and helped us get what we needed for our trip when our plans changed.
As a result of our changed plans, I have not yet been able to actually visit Vietnam and use the approval letter. However, I can attest to the fact that the website is very professional and not at all a scam. When I go to Vietnam, I will be comfortable using MyVietnamVisa.