Very loud hum. There doesn't seem to be a way to control fan speed without including it in a separate project. The case itself is good, but the fan. UPDATE: I've searched the web and didn't really want to delve into the extra parts. and a python script as I want it to be as light as possible. Luckily I've seen similar complaints from other users about the fan being too loud and they posted a picture showing how to use the fan on a 3.3V rail instead of 5V and it's a lot better. Now it is not audible, but the temperature is slightly higher than before (perhaps the difference is no more than 2-5 degrees). Originally 3 stars, upgraded to 4 per ability. It would be 5 if they could include alternatives to placing the fan. Again, this is just for the fan - the case itself is superb. Feels really cool at 5V with a fan even after running the server for hours. Before I got the case, my Pi was maxed out at 60 cents. A case with a 3.3v fan averages 47 c.Tl;dr, great case, noisy fan which is great for the 3.3v rail.