Well it depends, there are a few kits out there with shields and better arc placement. I'd be curious to see the beam pattern on a wall from like 40ft back. But like I said at the beginning of the OP, if you're someone who cares to do things the correct way then you can do just about anything. Here is a good write-up I found of a guy using HIDs in reflectors...but done right...something 99.9% of those installing HIDs wouldn't think to do.
http://forums.nasioc.com/forums/show....php?t=1666574
There are some exceptions to all of this, but my original post is "generally speaking". The only thing that really is bad all around is the stupid colored lights.