If you use a VoIP phone line (e.g. WxC VFX or 2talk), have you needed to do any special configuration to use it with UFB? 
I am planning on switching UFB provider, but unsure if my VFX phone line will work on Spark or Vodafone UFB.

I tried Bigpipe ADSL once, and had to tell them it wasn't working before it would work (Public IP set up - but not static).

What is your experience with VoIP after switching UFB provider?

I have the Myrepublic free trial at the moment, it works great and did not need any special configuration.