Does anyone have/has used the nursing bras with a zip underneath..? my mum suggested that these type of nursing bras are more discreet that the clip strap ones as you can hide more by pulling up, rather than down? but im not totally sold... anyone got experience that could give me a yay or nay? Apparently they are harder to unzip with one hand if you are holding baby with one arm already...and the same for fastening back up...? Thanks!