I have used vietnam Impressive (travel agent) for the last couple of weeks to purchase train tickets and Halong boat trip, visa on arrival ect.
I must say the lady I dealt with (susan ) was absolutely superb, emails answered straight away. Perfect english,and really could not do enough for you.
I was very worried about certain things as my time is very limited, but she allayed my fears and gave me extra tips.
I would highly reccomend them, in fact I wish that we had this kind of service in the UK.