Field of view
 

Did a quick test of the field of view at max wide of three camcorders:
(Field width in inches on a yardstick placed about 28.5" from the lens front element.)
These are relative numbers, and your results will vary depending on the overscan of your viewing system.
A large number means wider view.

XH A1 - 35.5
XA10 - 36
XA20 (Dynamic IS) 37
XA20 (Std IS) 39

The XA20 is a bit wider - nice to have.