First, they tried to overcharge the taxi (15$) from the airport, saying they wouldn't book the room if we didn't take their taxi. Fortunately the pickup never came, and we paid 110 000 dong (less than 6 usd).
Second, the room (20$) is expensive for what it is: 10 sqm, no soap, and the room was never cleaned in 2 days.
Third, it's very, very, VERY noisy (and we live in Hanoi so we are used to the noise). If you're on the front street it's even worse! You will be sleeping in front of a big bar/night club.
Finally the service is very poor. The manager has a lot of energy and wants to make things OK, but her staff is just incompetent...
However the manager organized a nice buffet for the Tet 2011, she is an awesome cooker(but skip the daily breakfast which is just not good at all). In a nutshell, not worth the 20 $...go somewhere else for that price, seriously!

Mybe long long time ago it was like the descriptions! Now in hotel 64 I spended just one night and it was enought! in my bad there was samething Who pinch my skin and our room was on the street, full of people moto music and jackhammers at work! Ok it's not their fault for jackhammers but the room it wasn't not clean like they said. And the price!!!! 25 dollars!! I can't belive! I travell with lonleyplanet guide and they put that hotel in their first choise!! It's not possile! And breakfast!! Ok no more word!

We walked in because it was in the Lonely planet.
The room was 15 usd ( but the price depends on the customer, we heard an old couple paying 25 usd). It was a small room but very clean on the 3rd floor.
Brekkie is free and good and you can have a free light dinner too.
For some reason we got moved to a dark room without window on our last night and there was mold but I slept fine anyway.
We did the Cu chi half day tour for 5 usd which went well and was good value.
If you room is at the rear it is not so noisy. I felt sorry waking up the poor gir lat reception at 3am when coming back fropm the bars but they close the gate at night.
Overall the staff is nice but the girl with the glasses is quiet robotic and pushes the sale of tours/transport a bit too much.
Also if you think they will keep a room for you when you go back from a few day trip you think wrong, they try to fill up and then send you to the least nice of the Madam Cuc but we walked away and found something cheaper and nicer.

We were quoted in dollars, but you can only really pay in Dong, because you can't withdraw dollars. The exchange rate they used was 5% over the real rate. We showed the manager the real rate, but out came the usual plethora of excuses. She ended up shouting at us in the hotel lobby. Truly shocking service. I'm a currency trader so I know how the system works. We've seen other places try this easy scam, but they always backed down when showed the actual rate.
They also try and chanrge 10$ for a taxi to the airport. We said we thought the normal price was 4-5$. Again a load of lies were reeled out as to why we needed to book with her about how we would be ripped off by local cabs. Sure enough we got a taxi in the street for 5$. Just make sure you agree a maximum fare in advance and then go on the meter. Never get in the cab that shouts at you for your business from over the street. Get the guy who looks like he's picking up locals.
You have to walk up to 9 flights of stairs to your room. Rooms are very noisy. Location is good. Place is very clean. You get breakfast and dinner, but they're very basic - the worst breakfast we've seen in Vietnam.
I'd stay somewhere else, you can certainly get a better deal on the same road.