Rendering times. That's the thing that's going to be the most annoying, but I think everyone knew that. Having done a lot of test renders, and still frame shots, based on the complexity of the textures and the lighting, I've been getting renders going as long as fifteen minutes a frame, although this was with some complex texturing - such as leather on the chairs, and paint on the walls. I've since changed a lot of it to fit better with the equipment I have.