MGS4 was a standout game for me. It was like the first must have for PS3. And I think the first few Acts delivered. The game felt grand, epic and there was a degree of freedom. Those commercials at the beginning, wtf. I loved it. MGS4 was bat shit insane but isn't that what we want from MGS? MGSV nailed the gameplay, its 10/10, but the craziness, ridiculous cutscenes and anime drama took a backseat. Its less memorable than the other 4 for those reasons.MGS4, with all its dumb shit, was much more charming. I bet a lot of gamers missed the stupidity of past MGS. Though V also gets incredibly stupid with Skull Face later on, but in a wrong and boring way. Its hard to explain. For reference check out the jeep ride.
MGS4 was so beloved, it took a GOTY award here twice. And its probably most port begged game out there if you remember the amount of Xbox fans claiming it would be ported over. Its still sort of a meme. For the record I do think its the worst game out of the first 4. For me its 2, 3, 1, 4.