I am a noob into the physics world and dont kow either of them very well. But from my perspective and the little bit knowledge that I have attained while working with 3DGS physics, my conclusion is that it is necessary for me to have polygonal level collision for static geometry. In newton that is not yet available yet. As far as compound collision is concerned, I dont know wether #DGS is capable of it. I dont want to set up the level for every possible situatin using Compund objects as its already hard to to create a game and then to see that every thing is set using compound objects would be un-necessary overhead, and in many situations not possible to implement.

Though for dynamic objects a compund collision would be very effictive. But still I would consider 3DGS physics as a better option for me.