lLT to ADT!
Please keep in mind before proceeding with the upgrade that both acad and adt have different approach. And the REVIT is tool from 3d parametric modeling approach. I hope you are aware of the change/shift. Please do proper research otherwise.
I would go for ADT anyway if i had to upgrade to any of these because of a familiar interface, small learning curve and compatability with other consultants.
regards
Harjeet Singh