Hi Rich,
Nice to see you posting here ...
)
Actually, I find porros somewhat easier to hold steady than roofs, provided the porros and the roofs are approximately the same weight. There's not that much difference, but especially when I'm using the bins over prolonged periods of time I also find the porros less tiring to hold steady.
However, the shape and weight are the most important factors. There are some roofs and some porros I find very difficult to hold steady, and others that seem to fit my hands much better. For instance, I never got to grips with the Swarovski EL's or the Leica 10x42BA. I just don't like their handling.
Hermann