I have the Duratrax Flashpoint like in your first link. It has been working great for years. Some people questioned the accuracy since it was so cheap, but heres what I found out.
I work as an automotive technician, every year my tools must be calibrated to SAE standards. While the calibration equipment was out I asked the man in charge to check my Duratrax. He asked me what it was bought for and told me it was as close as most of the guys $150 temp guns.