I recently got an AquaComputer Aquaero 6 LT USB Fan Controller to handle not only the fans, but the pump as well as monitor all of the temperature sensors (8 in total) and flow meter. The sheer number of temperature sensors is what persuaded me to go with this controller. While Digital Storm has a fan control board of their own with dedicated mounts in my chassis, it lacks a lot of the advanced functionality, including flow metering, and a nifty relay that can be put inline with either the power switch or PSU sense line to turn the computer off if, say, you wanted it to turn your computer off if it senses the water flow has stopped.
I initially wanted to place it in place of where the USB hub was to the side of the GPU toward the front of the case (I'm still using the USB hub, it is smaller and can easily be relocated elsewhere in the case). However, it is just a few square millimeters large in a specific area to clear a tab, so I needed to relocate it. I had no idea how it would fit, but as luck would have it, it fits perfectly beneath the optical drive, even with the connectors sticking out of it.
I even prefer this mounting position...I would have never thought of it without having the unit in my hand. It gets fully concealed when the optical drive and it's bracket are in place.
(Those threaded posts on either side of the perforated part above and behind the ODD bracket is where the Digital Storm unit mounts)