Upgraded from CS3 to CS5
1. Cleaner, manageable, customizable and easier to use GUI
2. Default keyboard shortcut is constrained
3. Mediocre memory usage ( Does not increase when considering a higher version )
4. Faster and much more responsive compared to previous version
5. A few new features that will come in handy
1. An Adobe Sign Up windows appears sometimes when opened
2. Very large install files. Extensive, unnecessary add-on application. Although it can be unchecked when installed, carrying it around might feel a bit dragged.