This one came with the Dometic 310, which, thank God, is now being installed in most of the new ones. If memory serves, every other one I've owned came with the Thetford "Aqua Torture Five".
Oh...wait...I meant to say Aqua "Magic" Five. Anyway, those were soon discarded, and replaced with either the Thetford "Bravura", "Style Plus" or "Style II". I've also tried the Dometic 210, aka "Traveler Lite".
You mess with me, you mess with the whole trailer park.