I used the Melexis MLX90260/MLX90261 back in December 2014 for some sensors research at work, and they were not very helpful and the documentation was appallingly ambiguous for important parts of the programming; plus, it offloads all the mathematics (not insignificant amounts of floating point and statistics) to your processor (not a good deal for embedded work). The output, once processed, though, was very accurate and provided for additional processing to make more use of the information than similar offerings.

The Panasonic Grid-Eye offering was much easier to use, and did not require additional processing power just to make use of the information.