I'm in the early stages of thinking I see worse impact from a brief VDSL2 glitch (20s resync) with a HomeHub5 using the integrated modem, as opposed to externally. In the former case PPP is recycled, in the latter it is not.
More info at http://community.bt.com/t5/BT-Infinity/HomeHub-5-VDS...
Out of interest do most of the new routers on the market with integrated VDSL work similar to the HH5, or will they maintain the PPP connection during a short vdsl resync (one assumes the atm style link is kept up for a short period)