I have such a love/hate relationship with MGS games... I played 2 and 3 and eventually bought the HD collection and have now played all the existing titles.
The stories are not hard to follow, you just need to pay attention to what is being presented to you and how it is being presented.
That said, the games are so long-winded that I just have a really hard time putting up with them. They are super boring but so fascinating at the same time. They're funny, too, but not to the point that I want to keep playing.
I don't know if I'll pick this one up. I think I might be over the MGS franchise and I think Konami is going to see the same from others. They've taken so many years to build this story that they aren't really appealing to any new players.