All I can add is that I've done multiday adventure hiking. been MTB'ing since it was invented. When I'm on my MTB it is not the same camera that is on a short or long hike.
And my real MTB trips I used to take were in the mountains of Colorado for day long treks.
So .. all dependent upon your "definition" of your hikes / MTBing and what you have to pack with you .. just the camera? or other stuff. One camera / bag may work in one situation but not the other.
My main backpack is a military backpack and is waterproof (not just water resistant). And I simply put a camera bag(s) in it as I'm also carrying everything else with it (food, water, fire, tent, sleeping bag, medical, etc etc) and sometimes climbing/rappelling gear. So not much room for a large camera or multiple lenses.
but all your options look nice to carry a camera and lens and other stuff.
They all have a padded kidney/hip strap so that is a good thing.
You'll want to pay attention to how the fabric is against your back as it may help either absorb and dissipate heat or simply makes your back all sweaty.
And you'll definitely want to test them as they may sit awkwardly on your back and hip area, and may or may not distribute weight evenly.
Good luck.
I'm looking for space for an APS-C camera, 70-200, two other 82mm thread lenses, sometimes a flash or two, and I'd love extra space to be able to store the 70-200 in a pocket other than mounted on the camera. I need some way to carry water (hydration pack preferred), tripod, and a small space for say food and an ultralight rain jacket or whatever else I may need. A day pack basically. Big bonus points for anything that's weather-resistant without the rain cover. I unfortunately don't have a local spot to try on this name brand stuff, so I've got to shop based on features and looks of the pack and hope it fits, and if not then return.
I've discovered that the F-Stop stuff is all backordered, and based on the horror stories, I'm not playing that game, so those are out. Which is kind of a shame, they look really nice. Just gonna throw out some other packs I've looked at in case someone comes across this thread later.
The Evoc CP 26L looks really nice actually, checks off most boxes, but I'm just a little wary about the shoulder and waist straps being mounted onto the back piece that unzips. Seems like it would cause a lot of stress on the zipper with a heavy pack, and I'm too worried about longevity to spend the money on it.
The Lowepro Flipside 400 AW definitely has plenty of space for camera gear, but not much else. It's the cheap option, and the only thing it doesn't have is storage space for other-than-camera gear. It's got that front pocket but it's pretty small. I do like the front center tripod-carrying system it has.
The Lowepro Flipside Trek BP 450 AW looks great too, but I wouldn't be able to store the 70-200 anywhere other than mounted to the camera, which kinda bugs me for some reason. I don't like having to change lenses just to fit it back in the bag. I actually hate changing lenses in the field period lol, I think I have mild OCD about keeping gear clean.
I think I'm down to either the Mindshift Gear Backlight 26L or the Lowepro Whistler BP 450 AW. They both pretty much have two rows in the camera area, since the Whistler is too narrow to have three lenses wide with lens hoods on, design failure on Lowepro's end there. The Backlight has more space for camera gear overall, except for a little less depth, but it seems like the Whistler has more space for other stuff. The Backlight has probably the best tripod-carrying system (IMO, I prefer the tripod centered), but then doesn't have the same amount of straps the Whistler does to attach other stuff. The Whistler pack looks more weather-resistant, though I'm not out in the rain a ton, and they both have rain covers. Just have to sit down and decide here I guess.