Hanoi and Saigon are bot great. If I had to choose I would base my choice on a number of conditions: Weather and time of year - both cities have slightly different weather patterns; budget and hotel preferences - great prices for 3 and 4 star hotels Hanoi is cheaper; and if you are into history, architecture, art - I would choose Hanoi over Saigon. I love Saigon it is a great Asian city while Hanoi is a bit like an older aunt - a bit more reserved, old, and at times eccentric. And of course there is the food - cuisines are slightly different - the south more spice and chilli. The other factor you may wish to consider are the side trips - a visit to the Mekong delta from Saigon or Ha Long Bay or Sapa from Hanoi. In short I would not compare them - pick which one suits your plans for your first trip and then go back and visit the other one next time.