Manual vs. Automatic Fan control

I own both the Lian-Li TR-3B auto fan controller and a Rheobus. I've been using the TR-3B since I built my system, but recently bought more powerful fans (Scythe S-flex and Mineabe). The auto fan controller uses probes to get a reading, but I am not sure if I trust them too much. I have also heard that with stronger fans, since the auto controller works on voltage, the full power of the fans might not be used.

In your opinions, which is the safer/more efficient option, continue using the TR-3B, go with the Rheobus and manually control the fans, or use a combination of the two (the TR-3B strictly for temp monitoring, and the Rheobus for fan speed). This might sound like an obvious question, but with cooling I don't know much.

Thanks.