I bought the tall fits 60L+ packstack and used it to pack my clothing on a 7 day backpacking trip this summer. Carrying capacity is much larger than expected, and it fit perfectly inside my Osprey Aura 65L bag! Definitely makes it easy to keep track of your gear.
Absolutely love the Packstack! I bought the 3-pack and currently using one for my sleep system, one for clothing/miscellaneous and one for cooking/food. Three of these fit perfectly in my Osprey Kestrel 38litre with some extra room. Well worth the money!