1. Clouds
2. Doppler sound. With MITSUs pack, the best overall sound in any flight sim ever.
3. Jumping into a gun, be it a ground AA vehicle or a CV or a bomber gunner. easily and no fuss. Always wanted to be able to blast away as a gunner

4. In game voice comms
5. Aircraft skins which are part of the terrain file. Ie desert camo, late war, early war depending on the CT terrain...... awesome.
6. Graphic effect when shooting water or dirt.... just like gun camera footage.
7. Able to Alt-TAB to desktop 100% of the time without crashing.
8. Me163 rocket fighter. Ive always wanted to fly this little bird.
9. Perk system allows me to try 'advanced' aircraft at my own risk, without destabilizing the arena.
I could go on and on and on, this sim kicks butt, but these are my top 9 likes.