Just started playing with mine and like it. It will do exactly what I bought it for.
What I found lacking in the Kill-a-Watt:
--Hard to see screen could be fixed by either having a tilting LCD or backlit LCD (or both); Quick fixed by using a power strip as a short extension cord.
--The Kill-a-Watt starts to keep track of time as soon as it is plugged in and doesn't stop until the device itself stops receiving power. Even if there is nothing pulling power through the device the stop watch will be running. Be careful of this when calculating your kWH/hours. I would prefer if the device would only track time when the "Watt/PV" values were other than 0.
Ex. I plugged a small fan into the Kill-a-Watt and ran it for a few hours. After turning the fan off I left the fan plugged into the Kill-a-Watt and the Kill-a-Watt plugged into a wall. The next day the "Hour" function read 15 hours but the "kWH" function had not changed since I turned the fan off. The average kWH/Hour would be drastically different between .1kWH/2Hours (right after I turned the fan off) and .1kWH/15Hours (when I next looked at the Kill-a-Watt after the fan was off for the night) if the kWH had not changed between the two times.
--The instruction booklet that comes with the device is the size of a paper napkin. Luckily there isn't much in the way of detailed information that would be lost if the napkin were to be destroyed.
--MIN/MAX function for the watts. This function would need to be able to remember the minimum wattage (other than zero) and the maximum wattage that the device measured while an appliance was running. This is important when trying to figure out how much juice something like a computer needs. For example, the computer that I'm using right now to type this review uses 88 watts when I'm not typing, 92 watts when I'm typing, 130 watts when playing a video game or viewing some type of on line media, and about 160 watts when booting up. This might not be useful when trying to figure out kWH/Hour but might be pretty useful when trying to figure out which of my appliances occasionally gulps electricity.
Things I would like to see in other models:
I'm not going to say anything about the device not being able to remember anything after being unplugged from the wall (there is another Kill-a-Watt that is supposed to have a memory ) but I think having some way to keep track of the watts being used every minute with a way to dump this information into a computer spread sheet program to make some graphs could be useful.
Beyond that, I can't think of anything else for this product that gives a way to see what is going on at the plug so to speak. I highly recommend this device.