Jan,
I never used that calculator before so I logged in to compare. It over estimated my total calories burned. I clicked on moderate activity and it estimated I would burn 2300 calories. According to BodyBugg, on a day with moderate activity, I'm burning just under 2000 calories.
On days I complete one hour of STS, 40 minutes of cardio, housework (meeting 10,000 steps a day) BodyBugg is reading 2300 range. I think one day I reached 2600 calories burned with 70 minutes of cardio coach
I like knowing what I need to do to burn x amount of calories.
I think the online calculators are close enough that you would make improvements.
For me, the digital display is there to constantly remind me of my goals and what I need to do to achieve them. I'm trying to lose the holiday fluff. If I want to eat more, I need to move more. If I want a lazy day, I need to cut back. I love when I look down at my bugg knowing I'm still showing a calorie deficit for the day.