Well, I managed to get a copy a little early, so I figured I'd make the official thread.
So far I'm enjoying it, haven't gotten too far into the game at all. But a few observations:
-Graphics seem to be a little smoother
-Skill books are still present, but they wear off; at least the ones I've found so far.
-So far food and drink doesn't seem that challenging. It is simply a bar that raises over time, just like the radiation bar. Remember that food and water that was basically useless in FO3? Now it has a purpose.
-You can make recipes and combine ingredients at a camp fire. Pretty much like Oblivion et al. Pick some plants, get some animal ingredients, mix them together. You already have a set menu at your disposition as you start.
-Damage threshold seems interesting... If you don't hit hard enough, you won't damage them, but if you hit above their DT it will breach their armor and take out HP.
-IIRC weapons above 75% CON are 100% DAM, armor at 50% will also be at 100% DT.
There are little tweaks to just about everything, but nothing that really pops out so far. All good additions though.