I've had a look at them.
While they are well designed packs and in the ultralight category (890 grams for M) there are a few considerable negatives.
-load carrying. Anything more than 11 kg load and your going to sacrifice comfort as the hip belt and shoulder straps have minimal padding. The straps and buckles are all thin as well.
- durability. Parts of the pack material are only 30d. So durability could be a factor depending on where your walking and how many scraps against branches it receives.. High wear points bottom and lower sided do use a much more durable 210d material
- it's light grey and from what I've heard they become dirty reasonable quickly especially the bottom.
I'm a big fan of osprey packs. I own a exos 48. My opinion is for most people the more durable and comfortable exos/eja is the better choice. It can comfortably carry 15kg. And weighs only 100 - 200 grams more. (Depending if you remove the top pocket, which I always do on mine for walks under 4 nights.)
Here is a good review and comparison between the exos and levity.
https://andrewskurka.com/2018/osprey-ex ... acrifices/