I've been mulling over the Sword and Pistol feat (and the related prerequisite feat snap shot)for the classic musketeer/swashbuckler build, and find it troubled. My main problem is the very expensive buy-in of feats.
First of all, i think i would drop Snap Shot as a prereq for Sword and Pistol. Why, because with most one hand firearms and all crossbows you're not going to get to shoot and strike every round because of the need for a free hand to reload (only a revolver does not require a free hand). (There are other threads dealing with tricks around this but none are particularly conceptually appealing and require magic item workarounds), so the feat is already extremely limited in application. Likewise even Rapid Shot is not particular helpful either for the same reason. Precise shot or combat expertise could be alternate requirements, since they deal with melee, or Rapid Reload, since it deals with crossbows and firearms.
As for Snap Shot, it seems to me it would make more sense to drop weapon focus out of the tree and replace it with Combat Reflexes and Weapon Proficiency (firearms pr crossbow). That way Snap Shot is more useful all around. The way firearms are built it's likely that as your character levels up they will want to use better guns or a mix and match of types. This feat limits them to only one specific weapon, which really doesn't make that much sense. The feat is more about reflexes than focus anyway.
Of course, Sword and Pistol assumes you want to also have Snap Shot, so my suggestions might make it harder to do both!
What do you all think?