I’ve only been using this outside for about a week, but it’s been through two rainstorms already and hasn’t had any leaks.  It has a snap top closure, so you just have to make sure you push in the right spots and listen for it to lock in place.  Regarding assembly, it has more pieces than I anticipated but the directions were straight forward.  The inside screws in the bottom corners could be a bit cumbersome for some, but I was able to sit inside to reach them easily.