The campaign of Call of Duty: Black Ops 3 is completely terrible, and that's not me even exaggerating. However, the online is pretty amazing and I find it immensely fun to play. I would recommend purchasing the game - it's definitely worth every penny.
In all trades, the risk of a charge-back on PayPal is possible and can occur at any time. The best advice is to trade with highly trusted members only as it significantly minimizes the risk of charge-backs.
Good luck trading.
As stated above, the best option for you would be to look at YouTube videos and/or live-streams and determine the rating of the game for yourself. The reason being is because a non-biased review from yourself on a game can conclude as to whether you wish to purchase a specific game or not.
Currently, you have an awesome username image. I was wondering, could you let me know who made your current username image? I would love to purchase one off of him/her.
Good luck getting your username image, though.