"1. Will that proprietary, mission-critical application run on
the new platform?
"One of the first things I tell people who are considering a
migration is: "Yes, most probably there is a Linux equivalent to
the application you use." Photoshop? Use Gimp. Adobe Reader? Use
Scribus. "However, there are certain instances where an application
has been written specifically for a purpose — or company
— and does not have a cross-platform equivalent. In this
case, you could try running your application with Wine, or you
could run a virtual instance of Windows to get the app running. But
this takes time and effort and, in some cases, isn't as stable as
one would like — especially in the case of Wine."