KC is decent, and free forever.
If you don't have a lot of ground click effects, and are mostly a PvE player, it works great.
For the most part, you use wow macros and control what is pushed by dragging a spell onto a given hotkey for some characters but not others.

IS Boxer is a subscription option, about $36/year.
It does auto FTL, so the slaves assist the main, without a need for macros to do this; which is huge for PvP and nice for PvE.
You can set up repeater regions, where mouse broadcasting turns on if your mouse is in the area -- which opens click based healing (via Healbot, Grid+Clique or Vuhdo) from any toon on your team.
You can set hotkeys (mapped keys) to turn on broadcasting for the next click (and then auto turn off), which is great for Hurricane, Death & Decay, Mass Dispel, Blizzard etc.
IS Boxer is much more flexible; you can send commands to Current Window, Other Windows (independent slave movement, if you run PvE dungeons a lot), or to toons in a group which you define who belongs to the group.
You can set up clickable icons (tied to mapped keys/hotkeys) on your screen, which opens a lot of options too.

The basic set up for either program is fairly easy.
IS Boxer has a wizard, and KC is basically getting the program to recognize the wow windows.
If you want to go beyond that, IS Boxer has a bit of a learning curve, but once you understand the basics of how it does something, it is quite logical.
There's a lot of support (here) and on www.isboxer.com, and on the IRC on the isboxer webpage. Keyclone has a telephone number on his site www.solidice.com/keyclone ,which gets you support too.