This is a recovery installer:
✔ Improvements to performance, recomended for large shows
✘ Longer and more complex install process, allow 48 hours
⚠ Relicensing required, please allow 48 hours for upgrade.
⚠ Show files will be deleted, user backup of show files required.
⚠ Only one historical software version maintained

This is an upgrade installer: 
✔ Faster install and simpler install experience, allow 2 hours
✔ Does not normally require relicensing.
✘ Does not include additional performance increases from the recovery installer.