I wasn't expecting much from this but after some experimentation, I now use it to effectively get rid of mascara before I wash my face. I also use it as a quick way to freshen up my face after work or, if I haven't been wearing make-up that day, as a lazy way to wash my face before night cream and bed!
It is very effective when used in those ways, however it is not a good substitute for washing your face/ using a cleansing wipe to remove foundation or bb cream.
Garnier Micellar water is a great and easy way to remove your makeup, and even better it's not expensive! I use a cotton pad dampened with micellar water all over my face, I have to use a few if i'm wearing a full face, and my makeup just comes right off. I will still use a cleanser after this to make sure I get all my makeup off before bed, but these are pretty effective by themselves!