I stayed at Sheraton Hanoi in August, and I felt their service was great.
It's just far away from downtown, and I had to argue with taxi drivers every night because they always tried to cheap tourists, and also I got fake money from them... Watch the meter all the time.
I used Taxi to get to the hotel, and I remember I used VND, but I thought I could have used USD. Ask information desk at the airport. They can tell you how much it costs to your hotel in USD and VND.
Good luck!