That chart needs a lot of help..
The WAN bandwidth of Docsis 2 is variously 42.88mbit/s, 38mbit/s, or about 35mbit/s depending on how you want to count (that is: absolute maximum including overhead, maximum after overhead, and practical approximation respectively).
For Docsis 3, the WAN bandwidth of the SMCD3GN and the SB612x are the same (all 4 channel modems). Similarly, the WAN bandwidth of the DCM47x, DCW775 and Huawei are the same (all 8 channel modems). The discrepancy in the chart is because different spec sheets are calculating differently.
Anyway, the maximum bandwidth isn't particularly relevant. What we care more about is what speed the cable operator will allow on a given modem. I've heard it said that Rogers cut off speed for Docsis 2 is 15mbit/s. Of course there are no packages at that speed, and Rogers will be allowing TPIA to use D2 modems on all packages upto 32mbit/s until April, so it is pretty confusing.
For the record, some knowledgeable posters here say that modems running up to, or at least near, their full capacity shouldn't really be causing the operators any issues, and imposing a bandwidth limit at below half the theoretical number is misguided.
I seriously doubt the MSRP on the DCM476 is $70. There may be an online dealer selling at that price, but that will be below MSRP for sure. There is no way the MSRP on the DCM425 is as low as $30--Canada Computers sells them at $48.99, and Canada Computers is almost always below MSRP.
(I sell DCM425 for $25 nowadays, but then they aren't new--better than new, but definitely used
Finally, I'm pretty sure that Teksavvy could start accepting the DCW775 any time they want to. Would be nice if we could have an update on that though (hello TSI-people