Really well built bags, I used one for a while but I ended up preferring the pro for most uses so I sold it and kept the pro. I only packed meat with that bag once but the waterproof panels on the back/bottom were great and easy to spray off.
The LT 5500 would be my pick if I was primarily backpack hunting. Its light and still has plenty of organization for your gear to keep the stuff sacks away.
In regards to pack access, its a question of do you want to lay the pack on its side or the belly (shoulder straps in the dirt)? The 5500 main access is through a long vertical side zip or a top shroud the front pocket also only opens from one side. Also the internal mesh pockets are oriented so you would access them through the side zip. The pro packs are all horseshoe zip that are best opened from the 'belly' position.
Water... there's no hanger or bladder sleeve (the accessory pocket or bladder rig is worth a buy anyway), I put my water bladder in the lid most of the time, there is a Hypalon port on the back of the lid for your tube. The side water bottle pockets are not cinch closures like they are on the pro, they are just non-adjustable elastic.
Last thing I will say is don't shy away from the 330D vs the 500D on the pro. The 330D is a more "slick' material that handles abrasion very well. The 500D on the pros is more typical Cordura feeling. I never worried about durability with either.
Hope this helps!