I have been paying $99/month for TWC's 50mbit. If they offered 300 at $200 I do not know if I would take it, there is a limit. If it was $125-$150, I probably would do it.
Even at 50 you see a lot of the webs limitations as many sites just cannot feed the information that fast. How much of it is overloaded links at TWC? Youtube still has issues....