Draytek Vigor or Billion Bipac best for diagnostic technician Router

I am undecided as to whether to buy a Billion or Draytek Fibre optic broadband router and exactly what I should include in that router?

Let me explain what I want to use it for.

I look after a number of schools where we use BT Infinity (Fibre Optic Broadband with speeds up to 80Mb). We use the BT Router (yes I have come to realise what a terrible idea that was, but in my defense the routers worked reliably for the first 2 and a half years without any problems and I didn't know any better about the differences between ISP supplied hubs and 3rd party ones!).

I have come to realise that the BT Routers have a number of problems

1. I have no control over when the Hub gets a firmware update (which has caused problems with one of my schools as the Internet has never been right since the hub firmware was upgraded)
2. They cannot handle a lot of network...