Sofa was packaged good and can be assembled by 2 persons without any issues, just follow the instructions. No drilling required in my case.
Quality is above average, but don't expect too much. Manufactured in Poland, parts are not ideally combined, holes are done ok but when you screw in the legs, you may strongly rub the upholstery of the sofa and damage it. Upholstery quality is average and quite thin, definitely requires careful use to last for some time. Well, I guess it related to the price tag.
As for comfort it exceeded my expectations. The sofa is stable and does not creak. It is harsh in a good way, you don't need a pillow for a back. Still 3 pillows in package are of low quality.
I haven't tried to sleep on it, but it should be completely fine.