I want to know if photobook print good quality (high resolution, accurate color) photobook as well as photo prints. I also want to know if smartphone snapped photos are enough in term of quality when it comes to printing them out. Lastly, for 4R photos, what aspect ratio should be (4:3 or 16:9)?
It all depend on how to upload the photo to website for printing.
Many choose to upload via facebook and instagram, where photo image has been compressed to minimum quality and it is not good to print out to any book greater than 6x6 inch.
If you upload your photo directly from phone / computer to the website, you will get full resolution quality image most of the time.