there is a $20 off $50 special going on (use code "getitnow"), so i just placed my first order today.
having to use the app is annoying, and the selection is pretty limited right now. it's mostly items that you might want on a last minute basis, such as snacks and cleaning supplies. my order consists of cat litter and hot sauce, haha.
i tried out google express earlier on, which saved me a couple of trips to the supermarket and costco. however, as time went on, the deliveries got delayed later and later into the night, and finally they would start missing the day altogether without any notice. i'd have to contact google to let them know so the order never showed up.
my amazon now order is out for delivery now, and the app shows the delivery guy on a map going driving around the neighborhood. pretty fun to watch.