Since moving out to the boonies nearly 2 years ago I've had cable one even with a house move the speeds have been at least as fast as advertised the vast majority of the time and now that I've cut the cord on TV and opted for their fastest speed (100/10 with higher usage limits) I've not seen it fall below 85Mb (usually it's in the 95-99 range) and occasionally get more than 100Mb. The weird part of that is my download system has a 100Mb card in it and the whole, overhead thing is generally not a negative number ;)
Once OpenBSD puts out the new release next month I'll switch routing duties from my tplink to a box with dual gigabit cards, and assign the firewall to be the main downloading box if I can find a good nzb downloader for openbsd can't imagine I'll see more than 100Mb, but a boy can dream ;)
With cable (I've used comcast, time warner, cox, and now cable one) except during really high usage hours you tend to get 85%+ of what they say you'll get (not counting their various wireless services). With *dsl (I've done S and A) I never got the promised speeds despite being the appropriate distance from the CO.I still hope to experience fiber (google or otherwise) someday but my chosen location makes that extremely unlikely in the next decade. Heck, I still am amazed that from the hot tub I can hear cows at night, and yet get a solid 100Mb connection. 90s me is very much in awe.