Fundamental failure with PSU location for thermal reasons. Dumping hot air at the bottom of the case. Sure its not a huge amount, but given that the power cables are routed at the back of the mobo, and cable lengths are not commonly an issue, the PSU really should be swapped with the HDD.
Have the PSU at the top, exhausting upwards. Its an internal mains connector anyway, so it doesn't matter which way it faces.
Then have three intake fans on the bottom, with the extra one in the forward position in the floor giving the HDDs fresh cool air. More fans, lower RPM, and filtered intakes in a positive pressure case will give you a quieter and cleaner system. Not to mention keeping HDDs below 40 degrees C.
That would make this case gold! Maybe its mod-able, for the adventurous ones... Its what I would consider first up.
Easier alternative is to reverse airflow direction of the PSU fan.
HDDs at the top does help to keep the HDD noise slightly quieter, but only really relevant for those seeking absolutely silent cases.
Other than that, its a pretty nice case