Gunships can be airlifted though
I voted explorer because I've only used it once (Islands map with many large and no tiny islands; they got eaten up by roaming barb axes a few turns after landing, bad luck on my part

), but I'll have to try using them as medics; I never liked having to waste 2 promotions to make a catapult-medic, and I like to have all my attack units buffed to attack
Never used Ironclads, either; they'd be a LOT more useful if they had 3 or 4 MPs instead of 2...
And as for Chokonus, I *always* use them when I'm China: the stack damage pretty much assures that I take the city (without losing precious cats), and the cumulative damage make it that I spend less time healing inside the city after it's taken.
I've used Musketmen well in my last game, but then I had the tech lead (3 or 4 techs ahead at prince O_o (that is, excluding my closest neighbor, Hatty, who was my equal until she backstabbed me to keep me from getting a domination win -- it didn't help her at all

)). By the time I got Riflemen, I had pwnt the Japanese and the Persians with them. That +1 attack they have over Macemen came in pretty handy VS fortified Longbowmen...