Been using testmy.net for years. The new-to-me graphic interface and long term test now available are really slick! I'm a desktop/laptop user. My backbone provider seems to be having some issues, ups and downs with the data rate making larger files, video, netflix and the like difficult to use. I'm an investor in my ISP who uses the backbone, helping out the techs.
On the graphic results page I didn't see a way to get the date and time shown in the balloons that pop up on the graph. I see they are listed in the chart below the graph. It would add to the "slickness" of this great feature if date and time of the speed test were shown in the balloon.