Be advised that converted computer/server power supplies can be noisy due to their cooling fans running at high rpm. While this isn't an issue in a data center/server room, it can be annoying in a more quiet setting.

Add: to be more specific, some smaller rack mount servers have fairly short power to save space inside the server case. These types of power supplies often have smaller fans that usually run at a higher rpm. Larger servers usually have larger physical power supplies with larger fans and aren't usually as loud.