If booked pre-release, was $19.99 to upgrade, and even that was getting some gripes.
Mind you, apparently the blu-ray licence is a significant chunk of that.
One other thing though, the way it was initially playing looked like Nero 10 was “going HD” altogether, replacing the non-HD, but now, it appears that the HD version is offerred alongside the “plain” version, as an extra cost option.
So unless you have Blu-ray to play and no other player software to handle it, or material that you are mastering to HD, then the standard version will be adequate.