Some people have been saying he's a lame card in general but I found TAA to be a very good CDM alongside Sissoko. With Shadow on him, he essentially was a CB but above the defensive line. His tackles were amazing and does a great job at stopping the attack from reaching the defense. He also has the added bonus of being a good free-taker and nearly squeezed in a couple of them for me. I'd say the only downsides are his shooting isn't the best if you plan on having him shoot more (if so, put Hunter on him) and 3* Skills. I'd say he's a good option for anyone who needs a PL CDM, especially if you want an extra green link to Van Dijk. He may be slightly overpriced but I feel he's worth it in the end.
Shooting (may be a tad better with Hunter but his finishing still isn't great)