I have an ultimate direction naviti that I love, and wanted to try a lumbar pack. Mountain smith just seemed too heavy, and I've always loved marmot products.
The good: shoulder freedom, well organized, secure bottle holders. Pretty much all the perks of having your bag sitting on your hips and not your shoulders. The way the pack falls on your hips, I think a petite female would enjoy it, unfortunately the hip belt cushioning doesn't really wrap fully around your hips if you have a waist that is greater than 28in. As with most lumbar packs, it's terrible difficult to get a secure fit into your lumbar area, and if you don't have the pack synched down super tight, when you jump a creek you get some pretty good bounce. I'm not sold yet on the strap that goes across your shoulder yet, at this point it seems more like a nuisance than functional, but I've only had the pack a little over a month. Overall I like the pack; it fits that unique niche that is a lumbar pack - I would buy it again, but it would be really nice if Marmot made the pack with different widths of hip in mind - like a small, medium, and large. I will admit when you're ducking into small spaces it is nice not to have a traditional pack that catches every limb that hangs down behind your neck.