I'd have to say I prefer alt mode, pretty much for the reasons stated above.

Having said that, I agree with Kup on the issue of QC - when I bought my RotF Megatron and Optimus, having them packaged in robot mode helped me to pick the ones with the best paint apps. I also remember reading about some examples of Skids and his unpainted teeth, so I was looking through the car's windscreen at his head when buying.