Id say either tranis or claymore have the best damage to energy ratio, and their projectile speeds and ranges are a little better than most of the others.
They're all okay (except for ONYX and JADE, they suck outright =P)
Dulzian has pretty purple projectile fire (and its a 4.00 I think?)
So that's why its 25m median on the world market. Just because its expensive and pretty doesnt mean its good...