I'd have to hear from those "far more knowledgeable people", because I'm personally using Ogre and it's just a rendering engine, nothing more.
You do know collision is a server-side thing right (though possible some client side checks for dead reckoning)
It's an isolated thing. The graphics engine and collision don't relate to each other.
You might not want to throw "far more knowledgeable people" at me too often :P
I know there's several that infact are, but there's plenty that only claim they are and have zero experience in actual game development.