After an extensive use of GH4, my thoughts are:

The camera is fantastic, I very much like the body is based on Gh3 (almost identical).

Video quality is exceptional especially in 4K.

The screen and viewfinder are exceptional.

Focus peeking is great, the strong version (which is light actually) is great for wide angle lenses, and the low version (which is strong actually) is very good for fast primes and macro work.

The camera starts recording 4K immediately after you turn it on or revive it from standby. Gh3 had an annoying message of please wait for several seconds. When you press the record button now the recording is almost immediately, I did not find the lag from GH3. I still don't like the dedicated video button, it is the worst video button I ever used on any camera. Fortunately on 4K video recording you can also use the picture button for starting and stopping the videos.

The colors are fantastic in standard and neutral mode.

The rolling shutter is very acceptable in 4K, I expected worst. In full HD is almost nonexistent.

I used NR -5 which I find as the best setting. It can be easily cleaned afterwards if desired and has a very fine monochrome grain structure. For me ISO 4000 is the maximum you can go on this camera, after that the noise jumps a in huge step.

I tried several profiles but I find Neutral the best setting for the camera. If the contrast of the scene is to high I dialed a little - contrast end everything is perfect. I tried a flatter profiles but I strongly recommend against it. The codec brakes, I got ugly compression artifacts and the noise is amplified in huge stile. After grading a flat profile I got nasty files, unacceptable for my work. The very flat profiles must be used with care and only on a external recording with 10 bit 4:2:2. The files contain a lot of data, especially in the shadows, so I can easily recover some DR in post if needed, much better than dialing to much DR in the camera. This observation is based on actual experience with the camera.

The camera consumes more current in 4K video recording than Full HD, I did not measured exactly how much more but I think between 40-50% more. My replacement batteries form GH3 work just fine.

I used a lot of cheep class 10 cards for recording 4K and never had any problem with them, heck I even used a 4 GB class 4 card until was full (4.45 minutes of recording). We've filmed more than 7 hours on a wedding event with two Gh4's. On a 64 GB of card I cold get about 1 hour and 37 minutes of 4K material. This roughly about one hour of 4K on 40 GB of space.

I used the new firmware and never had a crush problem on any camera.

We have and uses several Rode stereo video mic pro's on Gh4's. There is absolutely no problem with them on the camera. The sound quality is absolutely fantastic, much better than on GH3's with the same mics. The dynamics and clarity of the sound is much better, the noise floor is much lower in comparison.

The AF of the camera is fantastic in picture mode. It is so quick with 12-35mm f/2,8 that is hard to describe, is almost instantaneous. Is also very good in low light.In comparison with a conventional DSLR AF, it is also spot on, I never missed focus on a relatively stationary subject ever. It is also very good on Full HD, but a lot slower in 4K. Actually is not that bad, I had lower expectation for the AF in 4K, it is slow but it is not that bad. It can be used with care in many situations.

Our photographer used a Canon 5D mark 2 with a 24-70mm f/2,8 lens and we will also extract stills form 4K. The resolution of the pictures may seem low but is acceptably for any print size that I can think of. They are very detailed with very nice colors and DR. In a way they look better than the pictures from the 5D mark 2, except for the lower resolution. The extracted pictures from 4K look that good that it is hard to grade the RAW files from Canon to mach them LOL, and they are JPG's (this is my personal opinion, other may feel differently).

I'm very satisfied overall with the GH4, it dos not have any major flaw but has many strengths (the main is 4K) and the price is just right. Others have expected better high iso, but it is unrealistic, it is very good considering the sensor size. I don not agree with many who praise 1Dc for low light, the difference is roughly 1.5 stops between them, with SB there remains only 0.5 stops difference but the 4K from GH4 is much much more detailed, after denoising it looks cleaner and more detailed than the 4K from 1Dc.

We own to cameras and plan prerecord other two, but man it is hard to get them LOL.

Best regards to all, I hope I will be useful to someone with those information's.

@ Eno. Excellent and useful real world appraisal. Thanks. Pretty much matches my own experiences to date with the GH4. Constructive criticism and debate is always healthy but the bottom line is we should be thankful for such an extraordinary camera at this price level. We have Canon 5d's, hacked GH2's and GH4's as well as standard format video cameras. They all have their strengths and weaknesses. Without question, my head and shoulders favourite is the GH4 but at the end of the day, it's no longer what you shoot with - it's what you shoot and what you can do with it in post. And this applied long before the GH4 arrived.

New comparison of the GH4 to A7s...very positive things to say about the GH4

Yep, I went with the GH4 for all the same reasons he points out.

@tired

It is just small first part. :-) More will follow soon.

First A7s video to impress me. Dramatic difference between the two. Now wondering if 10-bit 4K will make much difference when it finally arrives with the Shogun for the GH4.

did they use a fix whitebalance?

I posted this in an another thread, but I think its better to post it here too.

GH2 (Moon T7) vs GH4

did anyone see details how he recorded the 4k sony? I can't seem to find them.

A music video I am shooting exclusively with the GH4 in UHD.

There are filler graphics which will be replaced with a cell phone tracked shot, and there is a black space where there is another two scenes to be placed.

Loving how this camera can be colour corrected so easily and then graded! I used filmconvert with the gh4 profile for the final colour.

5000fps

@shian Thanks for the post.