I've played it in one cube deck (and one Ixalan draft deck), but I don't think I got an accurate picture from that. It was in a 1v1 "pancake" draft and my deck ended up enough better than his deck that it never felt like Deadeye Tracker made a huge difference. Not to say that it was or wasn't worth the card, but it felt like I could have been down 0.5-1.5 more cards a game and still won. His deck was a mono red artifact synergy deck that didn't come together (I was taking/trashing a lot of cards he needed) and I had a typical UB control deck with removal + card draw + finishers. In general, control tends to be tough for synergy decks when they aren't focused enough. But in this case, I also had Inquisition of Kozilek, Hymn to Tourach, and Tasigur, the Golden Fang which were all problems for him on their own.
In theory though, it felt good to have in my deck and in my cube---perhaps more so than it would for others because of how my cube is set up. My cube has no planeswalkers, which makes repeatable value sources like this better in comparison. My cube also opts for more value threats than average, many of which derive their power from the graveyard, so a poor man's Deathrite Shaman still has a lot of value. In general, I try to include as much maindeck-able graveyard hate/exile effects as possible. On top of that, the sizing in my cube might be smaller than average and with fewer large flyers, so I think there is more combat interaction and thus Deadeye Tracker's body is more relevant here than it might be elsewhere.
(Note: CubeTutor link and blog are out of date.)
In theory though, it felt good to have in my deck and in my cube---perhaps more so than it would for others because of how my cube is set up. My cube has no planeswalkers, which makes repeatable value sources like this better in comparison. My cube also opts for more value threats than average, many of which derive their power from the graveyard, so a poor man's Deathrite Shaman still has a lot of value. In general, I try to include as much maindeck-able graveyard hate/exile effects as possible. On top of that, the sizing in my cube might be smaller than average and with fewer large flyers, so I think there is more combat interaction and thus Deadeye Tracker's body is more relevant here than it might be elsewhere.
(Note: CubeTutor link and blog are out of date.)