The movies definitely range in quality, with the first being iconic, and the rest trying to, but never able to, live up to the quality of the first one. Personally, I think that Scream 3 is the worst of the group with Scream 4 doing a good reboot of the series using the legacy characters but not having the legacy characters dominate the new group of younger actors.
This set is imported from Canada, and it is the easiest way, if you are in the US, to get all four movies in a single collection. In the US it is possible to get 1-3 as a collection, but 4 (apparently because of a rights issue) is not bundled with them. This set appears to include all of the same extras that the US blu-ray releases got including the commentary tracks, behind-the-scenes featurettes, Q&As, and promo material. The commentary tracks were always the longest bonus feature. Williamson did the commentary on the first movie and Craven (and various cast members) provided commentary tracks on 2-4. The movies all looked and sounded good in HD. Obviously, the more recent movies looked better. The movies are now getting released in 4k, but I think the blu-rays look fine, especially being upscaled by a 4k player on a 4k TV.
While the franchise is not perfect, it has, on the whole, been good. The misdirection in the first movie was the best twist that the series has come up with. In the subsequent movies the writers tried to (in my opinion) get a bit too cute with the twists, misdirection, and big reveals. Sometimes they worked better than others. The movies are definitely very violent and bloody, and there is a lot of swearing. There are some sexual content and jokes mixed in, but no real nudity. There is also some humor mixed in, mostly dark humor, especially in the first few movies. The movies will definitely not appeal to everyone, but if you are a fan of the horror genre, and 90s movies and TV series (the stars of which basically made up the cast of the first three movies), then this is definitely worth the pickup. Especially, if you can grab it at a reasonable price.