Gate Overflow is a site I've come to know and love during my preparation for GATE 2017.
I got AIR 77, with GATE score 865 and 71 marks out of 100.
I'm thankful to GO for their free guidance and providing excellent tests and platform for discussion.
Every year, GO answer keys always turn out to be correct and since 2 consecutive years even IITs changed the official keys after members from GO challenged it, so one can be assured of the credibility of the answers by GO mentors.
GO prediction tool was also very accurate and it predicted my rank to be 64-86, so all in all GO is a great initiative and the best part is that they're here to help students free of cost.