This game is basically the Metal Gear Solid HD Collection (disc 2 even loads as Metal Gear Solid HD Collection on your PlayStation and includes the Japanese Metal Gear and Metal Gear 2 under the Snake Eater game) plus some extras. You get a separate disc for Metal Gear Solid 4: Guns of the Patriots as well as a download code for Metal Gear Solid 1 (just requires an internet connection). Be careful about buying this game used though! It's more than likely that someone has already used the download code for MGS1 on another system, and if you still want the game it will cost you $10.99 on the PlayStation Store.
For the price, it's a great bargain granting you a total of seven games for your PlayStation 3, and three of them (MGS2, 3 and Peacewalker) are remastered in high definition. The only trouble is the discs are dual-layered Blu Ray and, depending on your system, they might not be readable. Many PS3 Slim and Super Slim versions struggle reading dual-layered Blu-Ray discs, though I haven't heard of any issues with the original PlayStation 3 console.