For a GPON service, FiberSink is the prime example of 'shit'.
For the last 4 years, the service has been working as such:
Good for 1 month (Not excellent, just good), then bad for 3 months. For 2016, March was really good. But mid April onwards, it has been shit again. I can barely stream Twitch.tv on 'low' without stutters, having a 50 MBPS connection I might add.
As soon as I switch on uTorrent, the nets goes to hell. And there is packet loss, yet again.
Overall I'd say if you have PTCL 4 MBPS, keep at it. Try to get it to work better. But if you invest in FiberSink, get ready to get sunk, punk hehe so many puns I think the nets is manifesting itself as a real entity causing mental retardism. Brb have to brush my nose.