For my business internet connection, we currently use a standard gigabit fibre connection. We don't typically get many complaints (~45 active devices at peak), but noticed Chorus offers SFP access now presumably only on Business Internet Service for a decent bit more. 

I'm curious what the main advantages would be for us? From my perspective, it'd be nice to get to use an SFP straight into our UDM Pro to save some physical space in our network cupboard (our current ONT is installed really poorly, not actually wall mounted just shoved between the network cabinet and the wall), and also mean the ONT is subject to our UPS backup (though granted, unsure how much other equipment is between us and the wider fibre network that may also be out of power).

We similarly have a regular fibre connection to our colocated servers, where again it'd be nice to use SFP instead. 

The connection options are much slower - I understand you're paying for guaranteed bandwidth. Does that mean, for example with my guaranteed 300/300 connection, where possible we'll still get up to 1Gb/s but during congested times only guaranteed 300 symmetric?