Here's the ones i use.
Everyone knows
Speedtest.net - The Global Broadband Speed Test Speedtest
That's the metrocast/bbr speedtest.
Speakeasy - Speed Test
Speak easy not as nice as speedtest, but pretty reliable.
http://www.speedtest.net/result/384235683.png <--my test
I get pretty consistent speed most of the time. There's a metrocast forums on BBR and some techs monitor it, but they can't by law really guaranty to help you there. They do it out of their own time and will. If i had DSL available i would have jump ship to it a long time ago, is way cleaner connection with a better ping than cable.