Kinda-sorta. Local Cable Co. sends 3 HD channels per QAM or roughly around 13Mb per HD channels. However, the variable bitrate "Cherry Picker" encoders do a very good job:
OTA: after multiples compaisons with a variety of OTA material, I have found no appreciable differences between OTA and the broadcast networks being shown on cable; they are virtually identical.
Cable HD: I was able to compare ESPN-HD, TNT-HD, HBO-HD and SHO-HD between VOOM DBS, Dish HD, and the local Cable Co. All were comparible, but believe it or not the PQ on local cable was sometimes better...especially when VOOM DBS was showing downrezzed some of these at 1440x1080i.
A big plus for cable is that I can rent three low-cost HD DVRs, with working firewire & and SATA (just plug in a hard drive for expanded storage), and pay no upgrade fees. A big negative is the HD DVRs are pale in comparison to the Dish 942 and their are only a dozen HD channels (5 are locals which I certainly don't need).