Today I received a Billion 8800 NL R2 to test. The TP-Link is easy to set up just go to quick setup and select DSL type and bridge and that is it. The Billion's Quick Setup is neither quick nor a full setup. You have the same Quick Setup menu option select bridge and the setup declares you have successfully setup the WAN connection, but you havent there is more to it.
As this page shows there are another two steps in order to be able to connect and for the modem to negotiate the correct speed. These steps are to set the VLAN ID 101 in most cases and to enable Group Isolation. As soon as I enabled group isolation my internet sprang into life. The remaining procedure on the page linked to is not necessary if you want to access the router and stats over the WAN cable.
Once I had configured the VLAN the speed of negotiation went from 54mbps to 64mbps, which is just 2mbps lower than TP-Link using same cables and setup.
So I summary the TP-Link is the easiest to setup, gets the maximum sync you can expect for VDSL2 but wireless at the moment may be a bit iffy. Hopefully, new firmware may fix the wireless instability if it is that. The Billion has had several tweaks in firmware to fix Wifi stability according to the release notes on the firmware. If the seller hadn't pointed me to the previously linked page I would still be struggling to set up the Billion in bridge mode!
www.uno.net.uk & freenetname
Asus DSL-N55U and TP-Link WD9970 on 80 Meg LLU Fibre
Current Sync: 71602/17848