Worst: I'm in a completely full-health Conquest flying broadside to the enemy fleet at the front of my flotilla. I was just overloaded from getting my attention pulled to something else while a few projectiles hit the shield. I maneuver out of the range of the enemy capital ships for a bit. I realize my mouse is pointing to the bottom of the screen, so I scroll to the top... revealing a cluster of about 12 bombers, all of which spit out their volley of rockets into a perfect broadside of my overloaded, pristine Conquest.
Half of a second later, Commander Revenant was killed in action aboard a glowing chunk of capital-class wreckage. That bomber group completely wrecked my *** in a single pass... Wow.
Best: Well, I beat all the missions. Easy is 90+%, Medium is 70+%, Hard is 50+%, and Impossible is 30+%. Aside from that, I pause the game very, very often to manage the battle. My own ship-flying abilities lean very heavily toward smaller, agile craft with a lot of punch because of the EV Nova and Freespace influence -- the Bis'Mar mission I managed an 83% on simply because I could singlehandedly demolish anything the enemy didn't suicide into my fleet. Crushing the Onslaught is laughably easy with that corvette, though frigate-sized craft pose a challenge because of the widely-spaced, short-range, low-ROF antimatter blasters that aren't suited for medium-sized craft (the PD beams take care of fighters and missiles ridiculously well, though). The Bis'Mar even has a gigantic unshielded half in the back to exploit. A few passes with my antimatter blasters and torpedoes turned the whole thing into a pile of slag, and I had virtually no armor damage.
Hornet's Nest wasn't that bad to clear (the Apogee is amazing), but Last Hurrah was brutal. The strategy I ended up winning with was capturing a few points on the right with fighters to call in my ships, then form a gigantic ball of ships toward the south while I go alone to take the left points and crush any straggling frigates. At that point, I would have to sprint back to the south where, by now, both fleets have nearly annihilated each other, leaving a completely unharmed me to assist my last surviving ships in taking out the remaining battlecruisers and frigates.
Dire Straits was clearable enough. I got away with most of my stuff, but lost a smaller transport, a larger transport, and the huge elite transport, plus several fighter wings and a couple support craft. The rest escaped. My strategy was to confuse the enemy into throwing all their stuff at one random transport + some guards way off on one side of the map while my other ships traveled largely uncontested down the middle and left lanes. Still, fighting off most of the straggling enemy ships singlehandedly took its toll on the Hammerhead, leaving me with only 700 hull by the end. Luckily, the battleships wasted their time chasing down the 15-cost transport for the better part of the entire game, meaning that I never had to engage those things.