ok, here are my first impressions. I had no time yet to use the GR4 outside. It is difficult to shoot photos during daylight if it is so early dark outside end of October.
There is a thread at reddit in which some users complain about:
- Frozen camera
- Lens won't retract,
- Difficulties to connect with the GR world app
- Image stabilization problems
- Rear screen freezing
- Lens getting stuck when turning off, only goes half way.
- Image processing error a few times.
- Strange colours on rear screen
- Uneven aperture blades
- Cover for USB port easier to open than with GR3
- Stiff top dial (program mode) dial
- Mist filter effect on some bright highlights
- ...
I checked all these points (except "mist filter effect") with my GR4. I can not confirm any of the above mentioned "problems", except the stiffer mode dial. I am always very cautious with postings at reddit. Very often you find there unexperienced users who complain before reading the manual or just do not have enough basic "photographic understanding". Most of them are new to the Ricoh GR line.
There might be some problems with some cameras (like the "freezing"), but that does not mean that it happens with all GR4 cameras.
The cover of the USB port is not as hard to open like with the GR3. I did not find at the beginning the USB port of the GR3, because it was so hard to open it. But you can not say that it is too loose with the GR4. Always take the comments on the internet with a grain of salt.
My only concern is the mist filter effect reported by Samuel in his videos. But I need daylight and a lot of sun to test this.
The GR4 feels "snappier" to use. I am sure if you measure it and compare it to the GR3, it is not a huge difference (on/off, AF etc.), but in real life you feel it. Whether the difference is big enough for you, you have to decide yourself. Officially the lens on the GR4 seems to be sharper in the edges. How much sharper I do not know. I do not shoot test charts. But Samuel confirmed this in his videos and we can trust him.
What I like a lot is the internal storage! Micro SD cards is no problem for me. I am used to this with my DJI action cams and older smartphones. I put a Sandisk 256GB Extreme Pro V30 U3 A2 in it. All works well.