I've been on VF since September and have been lucky enough to obtain my PPPoE username/password from Vodafone.
Keep an eye on that HHG2500. It hated my line which had been fine on Infinity for 4 years. The VF box dropped sync several times a day and ended up with my line being banded. Switching back to the HG612 and getting OR to reset the DLM has got me back to full speed. Slightly faster, in fact, as the OR engineer performed a pair swap.
VF have handled things rather poorly. Some of us were given our PPPoE details after repeated attempts, whilst many others are being refused. Their Ts&Cs don't explicitly state that only their equipment may be used, and their pre-sales team are incorrectly telling potential customers that using their own modems is entirely supported. I even had their level 2 techs say "we don't care what you use, as long as it works for you and you reconnect our router before calling support".
All a bit of a clusterfudge, really.
Anyway, it would really be great to get these HHG2500's unlocked. With the HG612, the service has been fantastic - it's a real shame that it's hobbled for some by the VF router.