I've used NOAA data to investigate how weather effects production and energy consumption in manufacturing environments.

I found the data to be of good quality, free, and a simple interface to interact with.

One day I went to export data from their web portal and it never seemed to be ready. I shot an email off with no expectation of a response, but a little while later I got a nice response from their system administrator that they were doing an upgrade and some jobs got backed up in the queue. My limited experience with them has been all positive.