mini dv compared to broadcast dv camcorders
 

Has anyone compared the new canon xl2 to the new jvc 5100, does the 1/2'' ccd cameras give you a better picture than the 1/3' ccd.

Yes, 1/2 is better than 1/3 in most cases.

Obviously the bigger chip will get you a much better resolution picture. As will the mroe expensive lens...better electronics.

The XL1 is a decent camera...don't get me wrong. But you can't compare it to the big boys...

You might be better off getting both cameras together and doing your own tests for image quality. Also look at the other features of the camera (manual lens options, 24p/30p, shoulder mount, ergonomics, does it fit your shooting style, etc. etc.).

From a technical standpoint, there are a lot of differences between the two cameras you can analyze.
Resolution
16:9 / 4:3 resolution
Low light sensitivity
Color accuracy/reproduction
Exposure latitude
Adjustable gamma options (you may want to optimize a camera's gamma response to make your image look good and like film, or to get the most exposure if you plan on color correction in post)
24p/30p shooting modes
Depth of field
Digital signal processing (higher bit processing is slightly better)

Lens:
Zoom range
Lowest f-stop / how 'fast' the lens in
Flaring - reduced contrast when light hits the lens
Ghosting
Breathing - slight zooming in/out when you switch focus
Barrel distortion
Vignetting / port holing (depends on focal length)
etc.

You really have to define what your goals are and then what features you are looking for in a camera. If you want good looking footage out of the camera without any post processing, then the XL2 may be your best bet as it has "film look" options to make the image look better (progressive shooting modes, film-like gamma curve/response).

2- Resolution-wise, CCD size shouldn't matter too much. A camera like the DVX100 shoots very close to DV's resolution maximum judging by test image captures at http://www.bealecorner.com/trv900/cats/cats.html

Resolution also depends on whether you're shooting 16:9 or 4:3. Theoretically the XL2 should have higher resolution shooting 16:9 than 4:3 (if you measure using TV lines per picture height, and do not fudge the numbers to get the 'equivalent' resolution of a camera shooting 4:3 for 16:9 output or vice versa).

CCD size does affect low light sensitivity and depth of field.

The XL2 uses less CCD area when it shoots 4:3 instead of 16:9.