I have tried 4, some seem to be buggy resulting in a game crash but hopefully this will be fixed over time. It turns out there are a few free mods, some are based on planes in the game but some do not seem to be. However I like variety and even though I have a reasonable amount of modules I like to try new planes. I have been practicing flying aircraft in DCS, I haven't relearnt how to use the weapons, but for now just flying around is enough.