I have been to Vietnam 3 times in the last 18 months and have used 3 different visa agents to obtain a visa approval letter prior to departing for Saigon. I have had no problems and do not consider it a rip off. The agent is providing a service for a fee.
The alternative is to get a visa direct from the embassy. By getting the visa at an embassy, you pay the visa fee directly to the embassy, the visa is affixed to your passport and on arrival you proceed directly to immigration.
If arriving with a visa approval letter from a visa agent, you must go to the visa landing booth to submit the required documentation and fee to be issued the visa.
It is then that you get the visa placed in your passport.
Suggestions if using a Visa Agent:
1. Print out the visa approval letter-the airline will want to see this as evidence that you will be admitted to Vietnam. I know of a number of people who have been denied boarding because they didn't have either a visa or a visa approval letter.
2. Fill out the visa application form that the agent sends you. At the visa application booth it is often chaotic. Have all the info required-it helps to get processed quicker.
3. Have the correct currency and the correct amount for the fee. If paying in anything other than US dollars you will get a really lousy exchange rate.
4. At airline check in, ask for an aisle seat near the front. You will get off a lot sooner than those behind you, and if you are organised, you will be out of the airport sooner. Not necessarily quickly but well before those who are disorganised.
My oberservations at Saigon:
1.People with no visa or approval letter being denied entry and being sent back to where they came from.
2. No forms on the counter.
3. People with no photos, no money, no pen, no idea what to do.
Sure, it's a bit inconvenient and using a visa agent costs a bit more, but in my opinion,
Vietnam is worth it.