There is a lot more in the 2080 than just the extra EFX and Expansion slots (which are worth the difference alone).
- The 2080 is using 18-bit DACs (vs 16-bit in the 1080).
- The 2080 has a better UI and large graphical LCD which allows for full easy editing PLUS midi message/information monitoring.
- You also get the Patch Finder etc.