Then I'd like to suggest a combination:
A "sort projects"-buttons leads to a new page where the user may drag/drop projects to reorder them.
The page also has a "sort alphabetically"-button which auto sorts the list.

Once the autosort feature has been used new projects will automatically sort alphabetically.
But as soon as you manually sort the list new projects are added to the top of the list.

This would account for those who want total control and those who want A-Z-style.

Win/win?