Had bought the Billion 5200S RC (Infineon chipset - I think) from BBB, but I have a long rural-ish line (~55dB downstream attenuation) with Broadcom equipment at my exchange but that was a catastrophe for me with severe signal loss at evening/night. Got RMA'd and settled on this Billion 7800 as an alternative product replacement instead.
This modem works an absolute charm on my line (via BE broadband, for now) at 4400KBit, Broadcom all round. Plus using the modem's PhyR options and the hidden SNR tweak and dropped it from 6dB to 4.5dB and gained about 300KBit on the downstream sync.
I wanted to keep the wireless network separate and the unit runs very cool indeed, so didn't go for the 7800N. Used RouterStats to monitor it over a couple of days and proves to give an incredibly stable connection day/night, I'm well pleased with it and would definitely recommend it on long lines.