This is now a real old game carrying a poor basic campaign/mission editor (and I don't speak about graphics) which is his principal default.
In front of the amount of work to reach the same level as IL2 (all work done by modders community!), which has almost (if I'm not wrong) the same age, what is the real value of this sim?
IL2, and SF2 survives, because there is no real alternative if you're interested in historical sims.
IL2 is perfect for 1914-1951 period, and SF2 for 1951-until now. For WWII for the time beiing there is no alternative appart beta Sims still Under devellopement.
And for modern history DCS could be the alternative, if they offered historical maps and campaigns. Unless you always could fly with P51, FW190, and Huey over Caucasus.....