I've used meguiers ultimate quick detailer, it's pretty incredible and keeps your wax layer topped up for a while too.
I use it to give the car a go over after i've washed and dried it to get rid of any streaks. and if the car has just been washed and it isn't too dusty then it'll be fine to use. I would strongly advise against it if there is any dirt/dust build up on the car though as spraying it on then wiping it off, even using a good microfibre cloth, could leave swirl marks and tiny scratches.
Hope that helps.