Predator is an early-midgame comp. It falls off like a brick and depends on hyper rolling. It'll likely get you top 4 if you get some 3 stars from it and most people aren't contesting it. Poison runs much better with Mundo, Twitch, Singed. If you want to keep your Predators you can definitely pick up 2 of those instead of all 3, but I find your damage will definitely suffer for it. It's better to do Poison + Rangers or Poison + Berserkers.
Summoners on the other hand are really stupid. Starts with 2/3 Inferno in the synergy, about 1/3 are early units too. Zyra might be the best tier 1 unit and Malzahar enables Shadow, which is possibly the best synergy available. Desert isn't too popular unless you're running Assassins so Azir isn't the hardest 3 star to pick up so you can have Summoners popping off pretty early. Yorick and Zed also are likely the best in their tier, however Yorick tends to fit Light comps better. But if you get a Light Spat on Zed and grab 1 other Light unit, its basically auto-win.
Their transition isn't the easiest to pull off, but its fairly easy and you can dip into multiple synergies that compliment it very well. Whether your secondary is Inferno, Shadow, or Light all of them will be strong. They've already nerfed it on PBE and its STILL really good if that tells you anything.