A good Galaxy Captain and a good escort Captain will stalemate each other. The Galaxy will cause enough damage to give the escort a scare but probably not enough to destroy it. However, the escort won't have enough firepower to cut through all of the Galaxy's defenses.
From my experience, in PvP levelling a pure PvP Tac/Escort char (well, Tac/BoP, slightly different from a pure Escort):
- Escorts put the "prey" in "Bird of Prey". Eng/Escort slightly more resilient prey. Defiants go boom, Hermeses go boom and Prometheuses go boom.
- Tac/Cruisers=long fight, but they go boom eventually.
- Eng/Cruisers or Sci/Cruisers=endless stalemate.
- Science Vessels=I'm toast. Especially Sci/Sci.
Anyway, while levelling my Sovereign char, I quite liked the upgrade to Galaxy. I don't understand how you'd feel weaker with a higher-tier ship, given all the upgrades it comes with (more BOFFs, Consoles, Weapons, Hull, Shields)... though yes, it does turns slowly.
Just be glad it turns faster than a Bortas/Bortasqu'.