Spare me the welcome beam, although this is my first post I've been a lurker for quite a while.
I don't have FS2, but I did complete the FS1 campaign with MOST of the missions on Insane. There were some that I just couldn't get past and had to go on Medium or Very Easy, but I finished about 90% of the campaign. Then I went through the campaign on Medium and made it through in like 3 days without dying or failing. Medium difficulty is fun because you get to massacre the AI hordes, but really, once you've played the campaign several times you want to try something new.
As for medals/promotions, here's how they work. I have a copy of VPVIEW (it's a free utility that lets you view the game files) and have looked at a lot of campaign missions in FRED. You get medals for doing specific things (usually getting all bonus, secondary and primary goals complete) on specific missions, as long as you are at a certain difficulty level or above. In the main FS campaign, you have to be at Medium or above to get the medals, so if you want to get medals, play on Medium. Rank is also affected by difficulty, apparently- you get points for killing ships and completing objectives, mostly for the latter (each fighter is worth like 10-20 points and a destroyer 1000, while most objectives are 300-1000 points). When I played the Insane level, even though I didn't kill any cap ships I did get promoted to Lieutenant JG about halfway through the campaign. On Medium, I killed 2 Typhons, 2 Demons and 2 Cains but only got promoted to Lt. JG very late in the game.
If you want to see the different point requirements for rank, google VPVIEW and download it. It's only like 2mb and is a really neat tool.
A few missions are actually easier on Insane. This is because Insane increases the skill of ALL Ai pilots, even friendlies. Play Last Hope (FS1) on Very Easy, don't do anything, just fly away and see how your wingmen perform. Now play the same mission on Insane and notice that the Hope will last a lot longer. Playing with both sides at high AI levels generally benefits the defender because the attacker is mostly doing bomber attacks which don't take much skill.
Oh, and if you have trouble beating Good Luck, either pick a Ursa in The Great Hunt and kill the reactors yourself, or fly in a fighter and get REALLY close to Reactor 5. If you get close enough, the fighters will ignore you and the only thing that will shot at you will be a missile launcher right above the reactor. Kill it and just sit there pounding the reactor until it's dead. Delta wing will handle the other four.
