First reason is their release of AIR 1.5 and its “run-ability” on my main system (WindowsXP x64). The OS is detected as Windows 2003 but it works, so thank you!
The second reason is their delivery on the original promise of Java (my fav dev language) to “run everywhere”. I can write code in FlexBuilder and it will run on any operating system that supports Flash Player 9 or 10, this includes 64-bit Linux! For instance I wrote an application that uses a library / project called Merapi to capture desktop screen shots using AIR and Java which works on OSX and WindowsXP; I can also be certain that it works on Linux.
Go Adobe, Go!