Wasted space is about 1/3rd of the drawer but you can use that for overflow bins/bags and less used parts. Just stuff them behind the trays in the front. I'll list you some additional downsides since you asked, but just so you know, the upsides far outweigh the downsides for me. Overall quality is good but the drawer floor is weak and may come semi loose from the bracket/need fixing after some time. This may not happen with LEGO though since it's not very heavy. Opening and closing the drawers moves everything inside back and forth (not a problem if you stuff the drawer full). You need additional trays/diviers on the inside which drives up the cost; if you want a perfect fit you'll have to get official IKEA ones or make them yourself which either way costs quite a bit. They aren't very suitable for huge amounts of very large parts (like huge plates and lots and lots of 2x something bricks) since that'll fill up the drawers really quickly. I have separate Iris Ohyama units for these big pieces. Again this is only a problem if you have a serious lot of them. You will run out of storage space as your collection grows (but this is not exclusive to any specific storage solution). But here are the upsides: Relatively affordable. Shallow drawers (this is a good thing for LEGO since you generally don't want to use deep bins, and also allows for more drawers in the same unit). Stackable. Smooth opening and closing. You don't HAVE to make a perfect fit with the trays and boxes that you put inside; almost anything that isn't too high will fit and you can mix & match containers. They look super clean. I have yet to see or hear about a superior alternative. Hope this helped. Ask away if you have any questions. Answer from TheParttender on reddit.com