I have used the Cannon cams for several jobs but never actually owned one. One reason to use an XL1/2 is that you tend to get a better reaction from the talent because it looks like a pro camera. I would never buy it for this reason but I am sure it is a big reason for many people even if they don't admit it.
Unless you need a long zoom or in camera 16:9 I would get the DVX100A. You save $1,500 and it is not so large so you can get away with using it in public areas whereas you will attract too much attention with the XL.
Here is a good user group for the DVX, XL2, and FX-1.
www.DVXuser.com