We had considered the M203, but went with the Def Tech 40mm, single shot.  There are more munitions options with the 40mm.  It is identical to the M79 grenade launch.  Simple, light weight, and you don't ALWAYS have to pack it if you are packing your M16/AR15.  Def-Tech is now owned by Armor Holding, who makes a BUNCH of stuff, including Break-Free.  Call them and they will come down and give a demo for free.[rocket]  IMHO, very cool.  Although, a M203 is nice as well.  We use our Ar's as patrol/entry/everything weapon, so the added M203 would not be for us.  Also, who ever has the M203 (unless everyone gets one, now that would work nicly!) is always your less lethal/chemical man.

Art in KY