Why would you assume the newer board is lower quality? Especially when you were asking very basic questions about it (footprint, PSU and gfx card options) it's odd you would know/believe one is inferior to the other.
Honestly, unless price is a major concern - there's no reason to look at anything other than a 460 board if you are interested in the ACube products.
Do make sure it fits your needs. I've seen a lot of people buy the NG PPC boards to try and relive old times of days past on a legacy Amiga. If you're buying one to run old legacy games and apps, you will be quite disappointed. I have a 440ep and love it, but a replacement for a beefed up A4000 or A1200 it isn't if one is looking to run the old 68k software. A fair bit of that still needs emulation, and the cost of a PPC OS4 machine is pretty high just to have to run UAE on what is underpowered HW by today's standards if you're a gamer.
All the answers to your questions are on ACube's website, as is the product manual.