I wanted a comparison chart but couldn't find one. Here's a stab at homemade.
Explanations:
Comcast Throttling:
"Sustained use of 70% of your up or downstream throughput triggers the Best Effort state (as opposed to the Priority Best-Effort State), at which point you'll find your traffic priority lowered until your usage drops to 50% of your provisioned upstream or downstream bandwidth for "a period of approximately 15 minutes." A throttled Comcast user being placed in a BE state "may or may not result in the user's traffic being delayed or, in extreme cases, dropped before PBE traffic is dropped."
So you can never use 100% of what you paid for? I'm so confused by this.
I'll update the chart as I get more info or as things change. Remember, I'm in SF area so speeds, whatever blablabla could be different in your area.