In Helium 11, there's a Length column in the Tag Editor (Aka Song Length), but it seems to be missing from Helium 12. I know you're not supposed to change it but I use it for statistical needs and calculating scores on my review site. It's the only thing preventing me from using Helium 12 at the moment.
This column has now be implemented. Please contact us from support.imploded.com if you would like to try a pre-release of it.