said by EG:FWIW, 8x4 multiple bonded channel capable modems are more "future proofed" than are only 4x4 modems like the 6121.
Yup, so modems such as the Motorola 6141, Zoom 5141J, or Linksys/Cisco DPC3008 may all be a better choice as they are all 8x4.