Anaconda vs Sidewinder has to do with the Conda's crazy pitch rate and fact that the Sidey needs to fly in a much bigger circle (read: more distance) than a static pitching Conda's that's mixing in thrusters. That scenario is totally biased in favor of the Anaconda, and I'd totally expect it to win.
Basically the same situation for the Python vs Gunship. Gunships pitch very well, and all in all are pretty agile (I used fixed weapons on mine even, back when I had one). If you on the tail of one, and it doesn't want you there, it just needs to pitch a bit to get you off it's six while, like the Sidewinder, you need to fly in a much bigger circle to actually stay on it's tail.
That's not me saying you're a poor pilot, that's geometry.
As for what I fly, recently it's been mostly Keelback, Python, and Viper IV (with grade 3 drive boosts, I don't trust Sirius Corp). Although I've flown everything except the CQC fighters.