Well I mean literally thats the only thing thats good about it, the look. It doesn't offer any physical advantage the only reason people like it (me included) is that it helps you blend into your surroundings if you are a sniper or another class, which is the actual only intention of a real ghillie suit as well. It is free so there is only one question you really must ask yourself: do you want to get 850 kills with the chrome barrel attachment? (that is the challenge that unlocks it).
You'll be harder to spot wearing a Ghillie Suit in grassy/jungle type environments. It's also great for when using silenced weapons as you can just go prone and pick people off with ease. I highly recommend it.
I really like it as well. For the simple fact that when ppl approach you, they don't know what type of gun you're holding. Then blending in with the game backgrounds and your surroundings make you feel so superior to your common fellow opponent's. I love making people panic when they see me coming around the corner.... Lmao
Actually it offers a tactical advantage also. Since the character hitboxes are all the same size no matter what character model you are using, the ghillie suit makes your character bigger than the hit boxes which means people can shoot at you and not actually hit you. I've seen videos of it being reviewed, tested it myself, and also had it happen in game before.