An accessible and immersive sim adds up to a lot of fun which rewards tactical flying.
Accessibility is enhanced by the simple, mouse driven interface and easy avionics. Immersion is provided by the dynamic campaign, the intelligence reports that come in via TV broadcast and internet, and the fact that you have a squadron of 6 pilots to last you the whole campaign.
Airbases become a hive of activity as the action heats up. After a while I started to make sense of the radio traffic and it was a buzz to hear your virtual teammates requesting permission to land.
It's this kind of dynamic and varied activity that gives you the sense you're flying in a 'real world' as opposed to a sterile world where all the activity is scripted.