This is a unique issue for OOL users, virtually no other cable company gives users so much bandwidth. That said, I've used the 3com and the Terayon, heres my take:
The 3com is usually slower, although less prone to packet lose, 3com is no longer making modems however.
The Terayon is usually faster, this is the primary SUPPORTED modem by OOL that acheives 8Mb/s.
Although the Toshiba has the same chipset as the Terayon, OOL does NOT support it, and therefore can not do future firmware pushes, nor can you.
So go for a Terayon, and if not, a Motorola SurfBoard.