Recently I had the opportunity to test the Lightning 60 in mountainous terrain hauling 35 lbs or so. Compared to the lightning 45 which I normally use and love, I found the 60 to be slightly less comfortable (needed the 60 for a larger bear can). Both packs utilize the same T-Rex suspension, so theoretically they should carry the same—more time spent dialing in the fit on the 60 is definitely in order since the 45 has been a dream to carry.
As far as the functionality of the pack is concerned—this is not the pack for someone who likes pockets. The minimalist design is essentially a large bag with two water bottle sized elasticated pockets on the side, zig zagging compression straps that allow you to lash various gear to, and a really beefy hip belt with a couple small zippered pockets for snacks on the trail. Imo what sets the pack apart from other lightweight packs is the brilliant suspension system. I personally love the minimalist design but I know it's not for everyone. My hiking buddy was rather irritated trying to figure out how the compression straps worked.
My only real criticism of the pack has to do with accessing water from the side pockets. I'm a bottle user and I find it very uncomfortable to reach back and access the water bottle pockets. I don't like using bladders so I'll have to figure out a clever solution because I find it to be problematic on both the 45 and 60 Lightning packs. Still, even with this one annoying shortcoming, I'm very satisfied with both packs.
This review was written in the old system and had content requirements that are different than reviews written today.