I already own 3 Mammut packs and love them. I bought the Lithium 25 as a slightly larger version of the Lithium 20 for warm weather hikes. The 20 has a relatively short length, which fits my torso well.
The lithium 25 is a top-loader with a very rigid back and it is too long for my stature. I am 5' 7" and this pack touches the top of my glutes even with the shoulder straps tightened all the way and the belt snugged agains my hips. I sent it back and opted for the Mammut Crea Light 28, which is everything I could possibly want in a pack. Tons of features and very lightweight.
If you are on the taller side this is a great pack (if not a little over built for its size and capacity).
This review was written in the old system and had content requirements that are different than reviews written today.