PNG is superior to JPG since the former is lossless with better compression and the latter has more artifacting. So for image comparisons, PNG should always be the option clicked on regarding Caps-a-Holic.com

I wouldn’t fully trust Amazon UK reviews. Better to browse various forums regarding the video and audio side in specific threads. Seems to me that person who left the review is a Twilight Time fanboy. More research needed though. (See if DVDBeaver mentions anything. Same goes for Blu-ray.com forum, AVS, HiDefDigest.)
I dunno, really.