I'm lucky enough to have an ISP providing me with gigabit fiber, as well as with a SFP of my choice, meaning that I don't have to use some terrible residential gateway like the one provided by SFR/Misericable when I was still in Paris, which was beyond awful at every single level, just like their support, infrastructure, stores, … everything was terrible.
Nowadays, I'm using my Edgerouter X SFP directly as my main router, and once minor issues were taken care of, it's nothing but great.
The first problem I encountered was that hardware offloading for NAT wasn't enabled, so instead of
having around 1Gbps, I maxed out at 100Mbps. This setting can be checked by running show ubnt offload,
and enabled with set system offload hwnat enable or system → offload → type in "enable" at hwnat in the web interface.
This yielded the expected 1Gbps!
There was an update available (v1.10.11 at the time), so I updated, rebooted,
and the upstream connection suddently dropped for exactly one minute at random
intervals. Instead of investigating and debugging like a grown up, I jumped the
hype wagon wagon and slapped the new firmware (v2.0.8-hotfix1) instead of
the LTS one, and it magically solved the problem. It seems that this is a know
issue: the Edgerouter LTS firmware leaks some weird stuff on the WAN interface,
triggering the port-security of the ISP, resulting in a one minute long
temporary drop.
Anyway, long story short, I'm now enjoying symmetric 1Gps, delivered by proper hardware, yay!