Actually, while the McCruise is very pricy, in my opinion it is worth the money.
I have had one on both my FJR and now on my C-14 and it is a VERY well engineered product.
Aside from superb install instructions everything is plug and play, no cutting or splicing required. But that aside, the biggest reason I decided to go with the spendy model was safety.
Now don't get me wrong, I'm not hating on either unit, the Audiovox and Rostra are both good units, and there are tons of these things in use today without a problem. Heck I helped a guy install one on a 2009 C-14 2 weeks ago. But the fact remains that these units were not designed for Motorcycles, they are CAR units and were adapted for Motorcycle use. They both have some form of chain or cable that hooks to the throttle arm and "pulls" the throttle when engaged, and while it is very rare, it IS possible for that chain to get stuck and hold the throttle open creating a potentially dangerous situation.
The McCruise removes this possibility, it's design calls for removing the throttles opening cable and replacing it with their short cable, then the original cable, their new cable and the servo cable all meet in an interface box that has 2 spools in it which rotate against each other. I am not explaining it very well I know, but the end result is the cables cannot stick and bind up the throttle.
Again I am not trying to dissuade you from using the AV or Rostra, but this is just something to keep in mind....