MGSV Ground Zeroes got a lot of flack for being way too short, and I agree. However what we have is really good anyway.
One of the many things I noticed was the replay value, and I think that its biggest strong point, however graphics, voice acting, story .... is all there. Being able to approach the mission objectives how you see fit in any fashion you'd like is also a key selling point for me. Sure its been done in other games, but MGSV gives you more freedom with this.
Honestly this game is well worth the money, and don't forget your save for this game may effect events in The Phantom Pain.