1. I'm used to just mashing the big red button on my HV20 and video being captured flawlessly. This doesn't happen on the GH2. I suspect that this is due to the shallower depth of field inherent in u43s. Most videos end up with obvious hunting and refocusing. Whilst the GH2 may be capable of great quality video due to its great (for video) sensor this is of merely academic interest when the camera struggles to maintain focus. I've tried the focus lock trick and it sometimes works and sometimes doesn't. So (for my needs) this is a fail.
If you are too impatient to learn to how to properly use the GH2 as a videography camera (as opposed to a camcorder):
Try shooting in Shutter Priority 1/60 of a second at a wide angle (14-20mm) using manual focus set to enable enough depth of field to keep the subjects in focus "enough." Thusly you emulate what your shitty camcorder is doing but still keeping the advantages of a big sensor in terms of high ISO capability and a relatively shallow depth-of-field.
2. The sensor seems much poorer (i.e. noisier) than that of my 40D. My rationale for the purchase of the GH2 for stills was that although the sensor was smaller than a 1.6 crop it was also a few years newer than that in the 40D and hence should be roughly on a par performance-wise. This doesn't seem to be the case - IMO.
The sensor in the 40D is just a couple of years old which is not that much. It is also a 10Mpix sensor as opposed to the 14Mpix (effective) and 50% smaller sensor in the GH2.
Sorry to point out the obvious.
3. Perceived image quality. With my 40D I regularly get images that blow me away from a quality perspective. I realise that this is (at least) partially down to the 17-55 f2.8 lens. However, I understand that the Panasonic 20mm is also highly regarded and I've never really been blown away by any images produced with that lens.
I used to have a 450D/Xsi and a 5D Mk II (along with Tokina 11-16/2.8, 17-55/2.8, 28/1.8, 200/2.8L etc.).
Yes, there is a difference in the CONSUMER perception -- mostly over-saturated colors and boosted micro-contrast. Some companies, like Canon and Olympus, chose to invest in research and implementation of CONSUMER-pleasing tweaks.
Others, like Panasonic, chose not to.
Search these forums of how to tweak the jpegs or raw (e.g. applying curves) to achieve the "Canon" or "Olympus" look.
For anybody else of us, the faithful reproduction of Panasonic is a good starting point.
Now, if you are talking about a limited dynamic range, then you are right. Panasonic HAS to improve it, especially the blown highlights, better soon than late.
4. Flash - The Olympus FL36R is ludicrously underpowered. I realise that it only has two AA batteries but it a) struggles to illuminate a small room with bounced flash and b) takes an unacceptable length of time to recharge. Also, there seems to be no reliable indication of when the flash is ready to fire again. I'm returning this flash as it's unacceptable for my needs. I could have gone with a 4AA flash unit. However this would have been as big as my Canon speedlite and would therefore have added no value to me.
Compared to a 580EX -- yes.
Compared to a 430EXII (which I have) -- no.
Recycling time is indeed slower on the 360 (8 seconds against 5 on the 430EX) but this is due to the 2 batteries against 4. Once you learn to time yourself and not "shoot and pray" you'll be fine.
Please compare apples to apples (FL-50 against 580EX).