I guess it depends on the kind of thing you're doing. If you're going through tombs in World Adventures, the moodlet manager trumps the motive mobile because it can instantly fix things like getting electrocuted, cursed, tired, lonely, even if you're levels deep in a tomb. Basically, if you're doing a lot of stuff on one lot for a long period of time, the moodlet manager is more useful. If you're running around collecting or something, or spent all night off the lot and your sim has to work in 2 hours, the motive mobile is better because on the ride home all the needs are instantly fixed.