Of all the 2.0 releases, Astro-Nautilus is one that seems the least changed. Go ahead, take a look. That's the problem when something looks perfectly fantastic the first time.
On the left is the original 1.0 version, on the right is the new 2.0 version. Can you tell the differences? They're quite subtle, and unless you put them side-by-side you may not notice. (Or I didn't notice, anyway.) The original 1.0 version from 2010 has slightly pinker skin, the 2.0 is more purple. The staffs seem basically the same at first glance, but it turns out the new one is a little more vibrant. Also, the space suit is different as the metallic bronze color is much shinier and more glossy on the 2.0 release.
Since the packaging is identical and the figures are nearly so, get either. Or both. 2.0 seems to be just barely more in line with the original figure from Colorforms, but this is one of those differences that your wife will mock you for if you dare try to point it out. (Maybe I speak from experience, maybe I don't.) I like 2.0 best.