Google has released a free version of Sketch-Up, called Google Sketch-Up. There is still a pro-version with some higher end features, but if you just want to get into 3D modeling, this is a great place to start. Try it here;
I received progress renderings from the outside rendering consultant that I sent an exported Revit model to. The renderings look good, and I have not heard about any major problems with the model from the firm. I created a custom layer export table where I put major building components on clearly named layers, like "curtain wall panels" or "mullions" rather than the 2D CAD layer naming standard that we usually employ. I assume this helped the rendering team with applying materials in 3DS Max, as it allows users to isolate geometry by layer.