cruising in neutral is not very bad but it does add to earlier wear of the breaks... engine breaking while braking is a safer option beacuse when you suddenly need to accelerate... like to avoid hitting something that split second of engaging the clutch and popping into gear can cause you that split second...

but it really does save you gas... it's what Mr. Ramirez did to the jazz he drove for petron... neutral on downhills...kaya nya nakuha yung 1114kms on one tank...