I got Walker on the first day of FIFA in a pack with two rare players.
In 111 matches, I was convinced that he is one of the best RB in the game.
He's fast, hardy, with great tackle and physics.
If you leave him in your half of the field, then feel free to buy.
But if you like to involve defenders in the attack, then this is not your option.
Kyle will be able to play attacking (he even scored once), but average dribbling and passing will not help you on a consistent basis.
For 120 thousand you will get an excellent defender, but do not expect something cheating from him.