I picked Custom Travel after a look on trip advsor and asking several companies to propose a whole Vietnam trip for us. Susan Ngyuen was very helpful in tailoring this 36 day trip to our exact needs. The whole trip was not particulary cheap, but it was excellent value for money. We toured the whole of Vietnam including more out of the way places like Dien Bien Phu, Dong Van/Meovac, Ba Be Lake and Cat Tien National Park, as well as the more usual places.
The logistics included 7 internal flights and 6 guides with cars provided with drivers to complete the top to bottom of Vietnam trip. Guides met us at each airport cmpletely reliably and in the vast majority of cases providing an excellent and informative service. Everything went completely effortlessly (from our perspective) and when on 1 occassion, we raised an issue, Susan dealt with it in a really customer friendly way.
I have absolutely no reservations about Custom Travel and am sure they would do an excellent job for you.
Out Guide in Hanoi and North Vietnam was Hom. In Paradise Caves, Hue and Hoian, was the excellent Nam. In Dalat and Cat Tien Vuong and in Mekong Delta, Lan have both become Friends. Ask for them and you won't be disappointed.