domalino already said it all. I posted this video a few months back in the Full Backs thread. And these aren't just selective highlights. He plays with this intensity every time I've watched him. He never went missing.
In fairness this video is more impressive than when I've watched him. He reminds me of Dammy Rose when I watch him with a bit of Arsenal version Clichy aggression mixed in.
This video shows him being great on the ball. Watching him doesn't support that view. He is a bit clunky on the ball. But very aggressive with and without the.
Energy wise he'll be a hit because we have a bunch of 30something year-olds playing fullback right now, and a guy that shows the type of energy he does would make our current fullbacks look like Geriatrics.
That said, perhaps him on one side and a much more fluid fullback like Bernat or Grimaldo on the other side may be the right balance. And I can see why many like him.
I'm much more partial towards Semedo at Benfica myself. His footballing technique is top notch and a shoe in for what we do.
@domalino referred to Sidibe as someone who could become our Dani Alves. But for my money I don't see a young fullback who is more like Alves than Semedo. Similar drive, confidence and technical skill levels.
Personally I'd hope for
Semedo, and in the absence of that, I'll take Pereira or Karsdorp over Sidibe. Perhaps even Heinrich at Bayer. These guys will be just much more comfortable in an intricate passing system in my opinion.
Sidibe's Kante styled tacking and size/speed combo are appealing, but I'd rather someone who could do some of that and a lot more quick tight space passing and dribbling. And for that, the aforementioned 3 (perhaps 4 according to those who have seen more of Heinrich) are superior to Sidibe at it. And none of them are defensive slouches by any stretch. Especially Perreira and Karsdorp. They bring that hard work to defending too.
Semedo is a bit Dani Alves like, in that he defends aggressively in spurts. But in a pressing system he will be top notch just like Dani often was. So I'm not worried.
But if it turns out to be Sidibe, I won't be disappointed like I was with getting Bony or Mangala. But I'll believe we could have gotten a few better options.