Owned both the BigNG and Aquaero 5.
Depends what you want it for really.
The BigNG is a better made controller buy design
Runs cooler
Univerally runs any fan (inc 24v delta's and San Aces - but not at full speed)
Runs fans at lower rpm's that most other controllers (30%)
has digital and anolog sensors
BUT it's a pig to set up and the software takes a while to workout.
Perfect for complex set and forget fan management
And the only controller I recomend for an ultra quiet build
Aquaero 5 - the software makes it easy - real-time changes, swap between profiles lots of help and frequently updated.
Can runs most 12v fans at 50% speed (and upwards)
But its Hot and power hungry.
And need optional extra's to do everything
Great if you have pumps / zoned cooling
Mid/High end boards usually have a o/b controller
Asus's 'fan xpert 2' is almost as good with most 120mm fans - look for boards with lots of 4pin fan headers.
MSI's (GD80) and Gigabytes onboard controller are also worth note
Speedfan (if set up properly) is also a great alturnative to any hardware controller.
Only have one or two fans to control so I use the mobo's controller.
50% unless cpu hits 70c then 75% job done.
Previous rig ran passive so even easier
