It is more expensive, and I don't know the features of Weight Commander, but here's what Diet Power does.
an easy journal
rating daily and weekly of the about 40 nutrients that you are getting too little of or too much
I especially like the the way I can add my own receipes and DP will give me a calorie per serving.
a food dictionary with 1000's of entries giving not just the calories fat protein carb counts but again a 40 nutrient breakdown.
an exercise journal that allow you to count housework!
You can try it free for 10 days
Try them both - if WC does as much for $10 - go for it.