About the new PMD, I wish I could give you a personal review, but I can't. So if you don't mind, I'll mention some stuff people told me (I too was debating about it).
So I've been told that there are very few Pokemon (150-200 and not all are recruitable). Difficulty has dropped due to disappearance of hunger (only few dungeons have it) and a new mechanic in monster houses that allows you to hit multiple Pokemon so it's become a bit pointless. Plus, the personality test has been removed and there are very few choices of character/partner Pokemon.
On the bright side, it has very good graphics and the Magnagate mechanism which allows you to make new dungeons is pretty cool.
As I mentioned, I haven't played the game. These are just quotes I was told.