The GillyGro Large Vertical Backpack Organizer Insert is definitely the best backpack organizer I've ever used. The quality of the materials is excellent, the construction is exceptional (not a single issue anywhere), and it's attractive. I would have preferred a more natural fabric, cotton canvas perhaps, but the feel of the material is nice and it's easy to keep clean with just a damp cloth. There's no smell, so little or no toxic residue; I'm shocked by how many things I order these days have noxious, toxic odors. None here!
It's large (measure your tote, backpack, suitcase or..., before ordering) and has a large number of different sizes of pockets and pouches, one insulated, one waterproof, and straps inside for water bottles (I haven't used that function yet). I used it for holding makeup, brushes and toiletries, underwear, small electronics and clothing items when traveling, and it was so easy to hang up and still be able to access what I needed. When hanging, some of the pockets open upside-down, so packing with that in mind helps. The handles on both ends can be used to hang the organizer up, so you actually can access everything if you don't mind reversing the bag to get to the pockets that are upside-down.
It fit perfectly in my travel backpack, and, though it did take up a lot of space, it was so nice to be able to find what I wanted without rooting around or having to empty everything out of the backpack. Laid out on the bed, it's very easy to take everything out quickly for storage. I always let it air out in between trips so there's little chance of any unwanted growth on the fabric.
I'm very happy with this; so nice not to be disappointed with a product but to find it's even better than I'd hoped for!