I have not tried much of the summoning skills but I have extensively used poly (I play solo not with companions).
Wings: Honestly I find this to be the least useful of all of the skills. I am not entirely sure why everyone is making a fuss about it. I hardly used it actually. I used the "movement" abilities from the other trees far more often. I pretty much only used Wings for running away.
Chameleon: Extremely good skill. Hopefully in the main game they give the rogue tree an earlier invis and chameleon comes later in poly.
Chicken: decent spell, fun to mess around with. I honestly didn't find it that overpowered.
Tentacle: Very solid awesome skill. Loved it. Made less use of it later on.
Skin Graph: This skill is ridiculous. At first glance I thought it was garbage but after messing around with it is has the potential to be completely broken. As demonstrated:
Elf rogue: first turn ---> Flesh sacrifice, Adrenaline, Burn My Eyes, Haste --->Vault(backlash), Sawtooth Knife, Throwing Knife(at this point whoever you targeted is pretty much insta gibbed or really close to it)--->Chameleon
Turn two: wait.
Turn 3: Skin Graph----> repeat turn 1 minus Burn My eyes---->Chameleon---> Walk in Shadows out and run away at mock jesus speed.
wait for cooldowns and repeat until everyone is eating carpet.
The only thing you must be wary of is not having a condition like Bleeding or Burning which will break your Invis. In your sequence, the melee attack can result in a burning/poison splash if your enemy bleeds fire or poison (ie. fire slugs, zombies). Now imagine this same mechanic with sneak+snipe as a ranger....it's ridiculously broken. Either the invis skills should be nerfed or there should only be one. Also, to be honest, I think sneaking in general is broken. The AI needs to be able to go on "alert mode" and run around to break your sneak somehow. I ran build without invis spells and realized you don't even need them. The AI just doesn't begin to look for you.
Also, in regards to Chicken, my opinion is that although Chicken itself is not broken, the fact that it's in the same kit as Chameleon and Skin Graft is plain absurd. The whole kit is broken. Also the extra attribute points for Poly are insanely useful if you're making a hybrid and need extra Memory.
