Iíve got a Marushin Unlimited revolver (the one with top & bottom rails) originally as a pure film prop, but Iíve fielded it in a couple games and I found it more a natural fit for me than the electric 1911ís or gas Berettas Iíve used in games before. The 8mm BBs have quite a kick. While the aesthetics donít matter to the enemy, Iíve found my teammates get a bit of charge when they see me pull out the thing and cock the hammer back.
I agree that, for the same weight/cost, itís not as efficient as an automatic pistol. Iíve got another extra six shells in a proper fitting speed loader, but that pales in comparison to, say, 49 rounds in an extended Glock mag.
Really, itís best used as a holdout weapon, when your back is to the wall and you need to pick your shots. I also find it great for initially sweeping/securing a room in a Ďcondition orangeí, but not that useful in a raw CQB fight.