The dark scenes are ok. They are in focus and you can see details. The black in a dark room is like an LCD black image not like an OLED or QLED black image. If you have an LCD TV from 2010 -2014, the image and the brightness is very similar. You also have the options in the menu to adjust colors to fit your screen and also the brightness.
I think that Epson TW 750 is better because you have more connection options, but you must have an external image source for movies which you can connect it to the HDMI port. Epson CO-FH02 doesn't have a free HDMI port and you need to disconnect the Android TV dongle every time. Regarding the image quality and brightness, they are both good, almost identical, although I think the colors look better on TW750 but the brightness feels better on FH02. So, I would go for TW750 if you connect your PC / laptop to it for gaming and movies.
Using the same image color settings for both projectors, I can say that the picture looks sharper on 6250 due to the 4k resolution, the brightness seens a little better on 6250 but it may be because it is newer then 750 and less used and the colors are very similar - for me they look like 5% better on 750 then 6250 but this is subjective to my eye sight. Not a big difference to be true. I would preffer the sharper image although they are both worth the prices they sell for. So if the price is not an issue, I'd go for 6250. It is 4k and it has an Android TV stick which works very good plus you have a free HDMI port to use with another device. More value for the money in my opinion.
If anyone wants completely new tw750 at discounted price (< 2h lamp used) contact me, I am selling due to unforeseen money requirement. (3 years warranty is still available)
