The one that you will be willing to use more will burn more fat.
And neither will burn it preferentially from your stomach.
FWIW, a good treadmill is much more expensive than a good exercise bike.
None, burning fat from an islotated area is impossible. To reduce it from your stomach your whole body fat percentage must drop too.
If i were to do a combination of exercise bike, ab-king pro and dieting, would that help??
Im not a fatty by any means, just want to lose that tiny bit of gut that i have..