Personally, I think if you already have Star Trek TNG on DVD, it's not worth converting to Bluray, unless you are a videophile and HAVE TO HAVE the extras, interviews, bonus features, out takes, cut scenes etc (I don't care about those, personally). The difference IS
noticeable for sure. I have all movies and series on DVD, as well as almost all trek DVD collectives, and I have all the movies, plus the first 3 seasons of TNG on BR. The movies are worth it to me because I personally think a movie should
look better than a TV series episode. But to me, I don't think I got much out of having TNG on BR. I may finish up the series because I am a completist, but I doubt I will get any other BR of any other series, unless I can find them second-hand, and inexpensively. But right now, I have better things to spend my money on, than $50 a season and repurchase stuff on BR that I already have on DVD.