Upgrading from Mathematica 5 to version 6 is highly recommended due to significant improvements, including enhanced functionality, real-time dynamic expressions, and superior graphics capabilities. Version 6 offers better error reporting, a more extensive library of functions, and a rewritten documentation system that is more user-friendly. Users can access over 500GB of curated data directly within the software, which greatly expands its utility. While some older notebooks may require adjustments for compatibility, most transition smoothly. Overall, the upgrade presents numerous advantages that outweigh potential drawbacks.