Basically, this "25th Anniversary Edition" is a joke because the only changes are a different cover, an included double-sided poster and already pre-installed "trophy patch", this can be the owner of the original version but also download for free. The new trophies are made varied and reward different behavior, there are beautiful, only very few automatic "Story Trophies" available. Thus, it is probably for many the incentive to risk his few passages and pursue different paths. The poster (approximately A3 format) shows on the one hand the new games Cover, on the other the faces of the 3 main characters, and the word "Metal Gear 25th Anniversary".
Conclusion: The game itself is a fantastic masterpiece. From an Anniversary Edition but would expect more, very skinny little is the difference to the original game.
For each of the "MSG4: Guns of the Patriots" is not his own calls: Get the same this edition. Has the same price as the original game, only has a poster attached and the trophy patch must not be downloaded separately. The game itself is as I said just a masterpiece, by the vast amounts of cinematic cut scenes.
For each of the "MSG4" already possesses: There are trophies patch as a free download, is worth buying a new non deifinitiv. The only difference is that you do not have to download it, the other cover, and the accompanying poster. Other Bonis there is not (unfortunately). Therefore: buying new useless!