Langster: Slightly road oriented geometry, Sugino Messenger cranks and arms, Sugino BB, Flip Flop hub, Carbon fiber fork and seatpost, weighs alot less than the Mark V

Iro: Cheaper, More true track geometry, Good quality components but nothing performance spec, no flip flop, steel.

Basically: Langster+Iro=GET WHAT YOU PAY FOR

If you want the faster lighter bike get the langster. If you want something your not gonna be upset if you scratch, then the iro. Both are great great bikes its just how your gonna use it.