Couldn't give a 5 star simply because of the gunslinger and guns. I know I can look over it, but it was still put in the book. Guns should be like Psionics, in there own book.
I would say the biggest upgrade from 3.5 is the classes and getting a feat every other level, it all makes for great customization. With this many reviews theres really nothing to add.
I think this book is pretty good, maybe not on the level of Core or APG, but I was comparing it to the Complete Series for 3.5. I was disappointed with no Prestige Classes as I'm one that thinks Archtypes are great but can't replace all PrC's. Not having magic items didn't bother me at all as there are magic items in tons of books. I won't get into details as that has been covered extensively, just wanted to give a 5 star as I think UM is getting knocked down alot because of how good The Core and APG are.