TEMPer v1.4 is a great little gadget.
I bought this of dx.com for under $10 with free shipping all the way to Denmark!
Here is a quick review of what i think about the device.

The hardware

The TEMPer device itself looks good, the casing is robust and strong, you feel like you can smash it in the ground without anything happening to it.
There is a sticker on it that does come off after some time, but this is not important since it is just a sticker and personally I just took it off as soon as it started to come off on it’s own.
The color is a dark-silver, and the USB connector is gold, it’s pretty and actually extremely heavy. So heavy you won’t believe it cost under $10!

The software

I have not tested this device on Windows, but i saw some screenshots of the software for it, and read about some people that had problems with the software.
It does not look very stable to me, it has bugs and design flaws and look incomplete.
Personally I only use this device on Linux. I had a hard time getting it to work since there are no official Linux driver/library’s or software to get the temperature reading of this device!
I made a guide on how to get this device working in Linux on a Raspberry Pi, but it will also work on a normal computer.
Mine has been running for some weeks now, using Linux and a Raspberry to get the temperature from the device with a command call from Nagios, this works pretty well, although sometimes the device is “Busy” and I have to wait a second before I can get the temperature reading, but this does not happen very often and it is not a problem to me.
You can find the guide on how to get it working on Linux here: Temperature measuring using Linux and Raspberry Pi
The reading are fast. When I run the command I get a reading immediately, there is not much of a delay maybe half a second!

Accuracy

The device I got was not 100% accurate! It show 6 Degrees Celsius too much every time I read the temperature.
Since I did not have time and did not want to use money to send it back and get a new one I decided to just subtract the 6 degrees in the program I have in my guide and then forget about it. (There is a guide on how to do this as well i the link above)
Otherwise, this device goes down to double comma decimals, like 26,55 degrees which is really great accurate for only $10 in my opinion!

Conclusion

I can recommend this device highly if you need a Thermometer you can monitor on the network, I have seen commercial plug-and-play devices for ~$450 which is insane if you only need to monitor your home servers, or maybe your summer house, garage or something else where the temperature is important.

Where to buy it

I bought mine a dx.com where I got free shipping to Denmark, it took about a week to arrive. But it was worth it!