I received my Skywatcher Quattro 150 a few days ago and had a chance to image with it last night. With the included coma corrector, it is 518mm at f/3.45
I used an unmodified Nikon Z50, since I don't have a dedicated astro camera. Located in NW NJ, my sky is only fair at around Bortle 4.5/5. Image shown is a stack of 25 exposures of 30 sec at ISO 6400, with some basic processing to darken the sky which would otherwise be very washed out. It's the full frame and had to be saved at the lowest jpg quality to get it under the image size limit.
This is a pretty nice little scope, especially considering the price.