I think the HH is a better router, but it has the same chipset as the Billion, albeit I find the HH syncs slightly faster. The HH also has better wireless and routing performance. You could always use the Billion as a modem and run it into the HH.
Personally I have used the Billion, but now use a Zyxel 8924 as it is a better router, IMO, and has better firmware.
Unless stats are important (and of course they are!) I would use the HH Type B!