Like GC said there are a lot of threads on it. I don't think I ever did a review after putting a season on it.
The 28 works great for me.
I like to put the platform and sticks in the load shelf. It keeps everything compact and well balanced. And I don't like carrying the snaggy metal stuff on the exterior.
Other gear and clothes I like to put in the bag. In extremely cold weather I sometimes have some clothing overflow that also fits in the load shelf. But I pack all my clothes in. I'm the guy that walks into my stand in a tshirt in 20 degree weather.
As far as the 14 vs. 28 to me it's a no brainer to have the bigger capacity. My wife has purses bigger than the 14. For a couple extra ounces I am going 28 all day. I actually wouldn't mind something in the 35-40L size for colder weather.
If I were designing it I would nitpick the pockets and zipper configuration a little, but they are plenty serviceable.
It's a great frame for its size. I didn't get to pack any whole deer out with it this year but it does 50 pound sandbags comfortably. My pack loaded with gear, water, and heavy clothes is around 30lbs and it carries like a dream.
I would say the two big downsides for this application are noise and smell. If you are religious about noise, the pack is cordura, and cordura is loud and moreso in the cold. I'm not super paranoid about it I just don't go digging through my pack all day once I get setup. And smell, if you are a scent control believer, I don't know of any frame pack that really works in that regard.