The presidential palace is located right next to the Ho Chi Minh mausoleum and the little house on stilts that Ho Chi minh lived in.
Ho chi Minh refused to live in the presidential palace when he was president and and build a little wooden house on stilts in the garden instead but these days the president of Vietnam has no problem living a luxury lifestyle way above the average vietnamese citizen.
The entrance to the palace also covers the visit to the house on stilts so it's worth going there even if you can not enter.
The palace is in a quite nice old colonial building but it has been painted in a fairly ugly yellow color that makes it look a little crappy if you ask me.
You can not enter the palace but view it from the outside on the way to Ho Chi Minhs house which is down in the backyard.