Honestly, I think this is one of the better sets they've put out presentation-wise, but it doesn't change the fact that the bonus disc is awful (mainly just cut together clips of all gadgets, villains, etc and the SkyFall video blogs, which you can just get online. No new insight, really disappointing.) and the special features are the same as the UE DVDs.
So, honestly, if you own the first batch and can get the final 9 cheaper than the set itself, it wouldn't be a bad idea to go that way. Keep in mind, though, that (as far as I know) the cases won't match the previous releases.
Anyway, I really, really love the box set, and think it's a hell of a deal for $150. Problem is, it's a great presentation, but it completely packs any real new features. So, base your decision on that.
All I know is that I'm fucked either way, since I own the previous releases, the box set, and... well, if they really release the standalones with the same covers the UK is getting, I won't be able to help myself. That'd make them, let's see here, my fifth full set of the films. Which, obviously, is totally necessary. Sigh.
Sir, you are worthy of your CAG handle.