I go back and forth, mostly depending on the pack. I don't really have a preference anymore except that I want water available at my shoulder. There are advantages to each, of course.
The side pockets on my packs have been either too shallow or way too deep for bottles, so having the hose on my shoulder was great for sipping on the go. Having the bladder in the pack also kept that weight centered next to the middle of my back and provided a little padding. However, since I couldn't see my water level, I always assumed I had less than I did and ended up drinking less. I also didn't love digging the bladder out of my pack to refill and there was always a little worry that it would leak. Again.
The last couple of years, I have been using a SmartWater bottle that was about to be tossed by one of my teenagers. I also nabbed a carabiner clip (from the same teen) that grabs the neck of the bottle. I liked clipping this to my shoulder strap with a little shock cord for the bottom. I could still drink on the go, and since I could see the water, I knew I should sip a bit more. I actually like carrying the water weight on the front.
Both systems attach to my filer; the bottle screws on and the bladder needs an extra tube. If I drop my pack on the straps, either system puts the nozzle into the dirt. I have protective caps for each, which help, but only if I use them.
My newest pack has bottle pockets on the straps as well as side pockets that work better for bottles, plus a removable hydration sleeve. So, I have options and will probably debate myself before each trip.
Edited by DustinV (07/20/21 12:16 PM)