I´d recommend installing the trial, because if you jump the pond, over to the Nuendo side, you will have to wait for a lot of new functions that are released exclusively for Cubase (at least at the beggining).
Cubase is updated to a new “.5” or full version every year, so owning Cubase is almost a guarantee that you´re in line for the newest cool stuff, that later almost always gets included in Nuendo, but the update cycles for Nuendo are much more far inbetween.
If you don´t really work on audio postprod for audiovisual projects, I wouldn´t recommend you go crossgrading to Nuendo.