Well at the beginnig I wold like to say that it was worth it. He is truly game changer.
Defence / Physicality/ Dribbling
His ability to takeover the ball is amazing. He can read every pass. In defence I can't say a bad word.
He also has incredible strength. Everyone is bouncing off him. No matter if you have 99 strength. On the field he feels little bit clumsy because of his agility. But when you can predict where your oponnent is going there is no problem. Just sometimes he have problem with turning. But hey he is not a Ben Yedder. He have 187 cm and he is a big guy. It supposed to be like that! :)
His shooting feel a lot better than his stats. He can finish basic passes. Also he can create some space by covering the ball in penalty area.
His passing is much much better than in basic card. Finally balls can reach target. In short passing he is very good. He can create some opportunities for your CAM or ST. In long passing he is ok. I mean you can do some long passing but the ball is slow in the air. I don't know maybe only I feel that. Overall he is good at passing.
He is quick. Acceleration is not the best It could be better but when he reach top speed you just cant run out of him.
I think this card can be use untill the end of fifa 20. He will be good for CM and CDM. In CDM can be problem with H/H rates. I recommend you to use him in CM. Sissoko's stamina is very good. In 70' you can feel him fresh.