I know I am asking in a Sony forum, but find most to be very honest and you would have the most information.

I do a lot of receptions in dark venues, always fighting low light, even with my video lights.

I also am very busy and capturing video is a huge consideration.

I now have 2 Canon XH A1's, and a Canon HV 30.
I may go to Canon 5D Mark II, Canon HV 30 and Sony XD Cam EX1

I do mostly photography, so the 5D II is a no brainer.

Hope to get some good advice in here.

Has anyone compared the XH A1 to the ex 1?

From my tests with the EX3, it has exceptional low light capability.

HD camcorder tests and comparison of Sony PMW-EX3 (PMWEX3) and Canon XH A1 Best values highlighted sorted by score (http://camcorder-test.slashcam.com/compare-cd7c1f069d5122fae8bb17ca23d57049.html)

I have and use both the EX3 and a Canon XH A1.

The Canon is a lighter camera and does produce some excellent footage, this makes it a much better for "Gun and Run" work. For producing SD DVDs, the Canon is an easier option.

However, for image quality and total control and of course being able to shoot onto memory cards, the Sony EX3 is superb.

I tend to use whichever camera is best for the assignment in hand, but if had to choose just one camera then it would be the EX3

I don't know what kind of lights you use but for quick set-ups the Cool Lights LED 600 with a battery takes some beating.
However although it's cheap for an LED it's still not cheap, particularly if you don't already have a V lock battery or similar.

I am leaning towards the XDcam Ex1, seems to do well in low light, have a great lcd and of coarse record to flash media.