Well this would or could be a very popular tutorial. I myself would be interested but there's so many different modelling programs that I would say it almost doesn't matter what app you use, you're never going to please everyone!!!

If poss, I would say use a free one but if they're not great then use whatever app you usually use, just try to show various steps and let everyone figure out how exactly they're going to have to do it in their app, or with a similar tool anyway