I've got over 700 hours into the pacg: 3 of the original base sets played 3+ times each through. I wanted this new Core Set but was going to wait, well now I've got it and seriously, every single aspect of the game is better:
The boons are better balanced, no more of the "this seems not useful, but, I guess if I encounter it I can use it once" cards, all are better balanced and this leads to more useful cards.
The box is better, no more wasted space with a big plastic insert, and they added a great system for holding all the cards without needing to buy a new wooden insert to organize better.
The rules are better, they do more, with less instructions, include more options. The new game options for "wild cards" and changing the size and difficulty make the game more approachable and easily recommendable as well as giving many more reasons to play the game multiple times. Very well done.
They included standees and chits and dividers too, all a nice and professional touch.
The artwork is at least as good as before, which I like, but slightly better laid out. I would like the text to be slightly larger (I had to complain about SOMETHING :)) and there is a little bit of wasted space on many cards, but the blessings in particular are nicely drawn, have a "stained glass" feel and everything looks a little nicer.
The entire game system is just more polished... everywhere really. It will be hard to go back to my old sets, which I will not be getting rid of, thank you, but everything in this set is simply better.
Edit: this is not so correct: "and have toned down permadeath (thank you...)".
The rules give you one extra option for coming back from death (hero points) but now that I'm about a dozen plays into the game it is clear (at least in Dragons Demand) that:
1) you only get one Hero Point to use without giving up a power for it through all 9 scenarios
and
2) there are quite a few banes that can cause ongoing damage that can kill a character who is not exploring
and
3) the new rules have removed closed locations, which used to offer some degree of safety to badly wounded characters.
I'm going to leave a 5 star rating for now, but I have to say, this makes the game harder to recommend to new players who would be super frustrated to have to completely start over again and feel like there was little they could do. If you are a new player, either house rule this away, or play very carefully. I hate, hate, hate having to start a game over again in this way, I wish permadeath were anything else....