WICH ONE?
okey, u can also only be the civ they represent so count that in your pick.
The Celtic UB and UU are not the best, but try free leaders with Boudica of the Inca for a Queshau Rush or Boudica of the Zulu or Roman.
Boudica's flaw is economy, you need to play very aggressive and press techs from a defeated civ and use a lot of espionage to compensate.
Don't build wonders, but see which Civ nearby has wonders interesting for you and conquer them.
Nothing can stop the raw power of Ganghis Khan's UU/UB combo.
I never thought the Keshik was all that better than a base horse archer. It does get a first strike, but it doesn't have immunity to them, correct?
The combination does have some punch, though, I'll grant you that.
Flanking II grants 1st strike immunity, making this the only unit in the game that can ignore them and still use one. Keshiks are virtually guaranteed to do considerable damage to any contemporary defender, and with flanking II even longbows aren't too much.
Keshiks benefit from the UB and the fact that they get 1 move cost on ALL terrain. They are a marked improvement on the horse archer, which is already an incredible unit.