I want to thank NZXT for sending out the Sentry II for us to play with. Current prices run at $29.99, making this a very inexpensive upgrade. An upgrade that will provide you with piece of mind since you can verify your fans are working and what the temperatures of your expensive hardware are. It also gives you that control to turn down the cyclone of sound when your fans are churning full blast and all your doing to stress your system is reading email. Turn on some Bad Company II, crank up the overclock on your CPU and GPU and watch as the auto control senses the increase in heat and compensates with increased fan speed, or manually set it yourself, which ever floats your boat.
My biggest issue with the Sentry II is when you rotate through your fans individually you get the temperature readout for that fans item. Kind of makes you feel the need to assign a temperature probe with a fan. You do not have to of course. You may not have a fan near your ram, but you can stick a probe on it. The problem is that if the ram temp picks up and you are in auto control then the associated fan picks up speed even though it can do nothing for the temperature of the ram. I know we are here to control the fan speeds, which in auto is related to the temperature of something near it, if I want temps for other parts of the case, or other components, get a separate temp monitor.
I found the Sentry II to be an excellent product, installation was a snap, packaging and the care of the contents were amazing and the ease of use is simplistic. This is a feature packed very inexpensive item. You gain control of the nosiest parts of your PC, the fans, and you can directly control them, or let the Sentry II do it for you in an intuitive auto mode. I am going to keep this in my PC for years to come.