Well the EX and the XDcam codec record the IMage part at 35mbps. the audio is uncompressed at 4channels and that makes the total something like 50mbps. I think.... I HOPE HOPE HOPE.... it doesnt compress audio too. HOPE.
the images should be fine for basic event coverage, and narritive stuff thats not composite intensive and CC intensive. though im sure it will look ok even if you go that route. XDcam isnt too bad. PLus you can go SDI out and record a low compression 4:2:2 Video signal thats 1920x1080. that will be pretty awesome.
I tend to disagree when you are doing a comparative with the HVX because essentially (keeping in mind here the EX is untested and I am only going by tech specs) whilst you are capturing more resolution to begin with and laying that out over 4:2:0 compared to the HVX capturing a lower res and using a different approach by stretching the captured 4:2:2 to cover the same resolution your ending up at virtually the same point, but one goes route A and one route B and a fair analogy would be something like - Route a is 20km but is a straight road so takes 20mins to travel whilst route B is 15 KM with lots of bends so also takes 20mins to travel. You could argue that the windy road is more interesting because of the bends another would argue the straight road is better because its more fuel efficient. And Id say fair enough, do whatever takes your fancy.
On specs alone Id go as far as to say: They deliver the exact same thing, though the EX is better equiped with the 1/2" chip and SDI out. By rights if your shooting green screen from the EX via SDI at true 4:2:2 and then factor in the chips it SHOULD have it all over the HVX.