Are the fans of the PSU really that loud? I have three on the way to power 5 ANTS. I wonder what will be louder the ANTS or the PSU's ...
Short answer is yes.
If your living around these server power supply fans, they become the ambient noise level. They are essentially about as loud as a hair dryer on low. Sitting out in the living room, in the middle of theday, with general noise around I started one up. I thought it wasn't too bad, definitely noticeable, but not too bad. Get them running for a while, and its not really that great as an example, to sleep near.
I set mine up in the basement with a bunch of vibration absorbing rubber material. With that, I cant hear them.
At full fan speed they are loud, but the airflow seems way over the top for the amount of cooling required if they are ~85-90% efficient. I'm not sure if Dell designs these units so that the fans are an integral part of the airflow through the server chassis, as well as just taking out the heat from the PSU. Anyway, using sidehack's breakout board to turn the fan down is important if you want to live near these things.