From an aesthetic point of view, I honestly don't mind either. In a way I really don't care since my focus won't be on the inventory, but on the game world. Even when in the inventory I'll be focused on specific elements rather than the inventory as a whole.
For anyone with free time on their hands I suggest this thread:
http://forums.cdprojektred.com/threads/30248-TW3-UI-Aesthetics
Long winded discussions in there where people didn't like the look of the old inventory and requested changes - more simplified colors, simpler imagery. Which amuses me because now people don't like the look of the new one (which promotes solid colors and a more minimalistic look) and say they like the old one better.
As I mentioned time and time again, CDPR shouldn't aim to please everyone, they will never win.
Now comparing functionality between the two, they seem pretty much identical, so there's not much to say on that front. Being a M&KB player I can see that they tried to please that certain demographic by making the inventory more mouse friendly (especially when comparing it to W2's inventory), so I can't complain about that. But I'll be more eager to discuss functionality once I actually get to play for an extended period of time and get the feel for the inventory.