I agree the connection type is worthless, so what is wrong with ping?
Why would you need to test the upload and download speed of the computer?
I thought that ping tested them both, and ping reflects weither the download would be good or not. It tests your connection to their computer, you don't need it to do anything else.
To not slow down bandwith, you could have users click on a new "ping" button to test the ping, so they don;t test everybodys