I have a Northface Terra 35, a Dueter Futura Pro 34, and a Dueter ACT lite 60. They all serve different functions. I use my smaller bags for one-nighters, and extended day trips, while I use my 60 liter for longer excursions. '
I love my Dueter ACT the most because it is lightweight, simple, has tons of room, is very narrow for fitting into tight spots, has a helmet/wet item pouch, and a back plate unlike anything else I've tried. It's also adjustable, so I can lend it out to friends and always have it fit them. The hip belt glues to your hips and holds the weight really well. It cinches down really small, and expands out an extra 10 liters for long adventures. I fell like I can use it for everything.