Trying to be fair there is more than one piece of software out there that you can use to pass keystrokes with that will allow you to multi-box, several of which I have heard good things about.

However the only software I've tried is Keyclone and will only be able to give my opinion on that program alone.

-"Noob friendly" - I'm not exactly the most sophisticated computer indiviual however I fel that Keyclone was not too terribly hard to set-up either. I had to read the tutorial a couple of times as well as some related threads to get it all set-up and running correctly but over all it was not a PITA by any means.
-A few extras - In addition to passing keystrokes to the other WoW clients it also has maximizer along with it which allows for resizing of the windows automatically each time you log in, features like round-robin for certain keystrokes for versatility, PiPs and BooBs which I actually don't use atm but that's just because I haven't really had the need to yet.
-Terrfic customer support. In case you're not aware the maker of Keyclone who goes by "Keyclone" is a frequent poster on these forums. He is very quick to help people out with software issues and is very open to ideas to make his product more multi-boxer friendly.

Again I can't give an opinion of the other software as I haven't used any of it, but the $40 I spent on my 2 copies of Keyclone was well worth it imo. MUCH better than when i use to alt-tab in between 2 wow clients prior to coming here