Well Brent, you've certainly come to the right place for a lot of opinions and info!
I don't get to hike nearly as frequent as others on this forum, but here's my experiences.
Before doing more hiking I did a lot more mountain biking, kayaking and carried a CamelBack. I think they have a superior product and have never experienced leaks with mine. I've got two different size packs for these and four bladders. My issues with them are that they need a little more maintenance than you standard water bottle, keeping the bladder and hose clean. I've purchased the CamelBack cleaning kits with the brushes, sanitization tablets and rack for drying. I can typically tell by the weight if I'm getting low on water. Only once, during a 24 hour adventure race, did I ever run dry unexpectedly, however my teammates each had water to spare.
When I go out on the trail I typically carry two large Nalgyene bottles for my water supply. My backback does have a pocket for the bladder, but I've found that it takes up too much room in the pack and I can place the bottles in the side pockets of my pack. I always carry a Steripen in my gear, so I'm never too far away from drinkable water. This allows me to only carry what I need.
While the Camelback bladder is far more usable, and when my pack is full I can not reach the side pockets for the bottles, I find that actually forces me to stop, off-load my pack every once in a while and take a break.
Perhaps there are better pack designs that make them more accessible. I have had good luck and really like the Osprey packs, so I will pick their pack with less accessible pockets, versus another brand that does. I have been using an Atmos 35 which is fairly small as packs go in order to force me to pack light. However, I recently picked up one of the Atmos 65s for longer trips and cold weather where I need room for larger bag and more layered clothing.
For reference.. here's my pack with waterbottles on it.
Also to note, when it comes to water bladders, I've found brand makes all the difference. Camelback is hands down the best in my experience. As thanksful I am for the folks that organized all the goodie bags for Seek the Peak, the waterbladder that came in the pack that they gave us leaks like crazy. I believe this was a Coleman brand, but I'm not 100% sure.
Hope that helps and let us know how your research project goes!