I have watched Sancho a lot for Dortmund, especially in the CL and particularly his first half season where he broke out.
He tends to do better with space, he's good at dribbling in close spaces but he's not an explosive dribbler. He's exceptional at assisting.
I just worry that in certain games, e.g. against Spurs in the CL last year, he was very ineffective. He's a top player but there is a chance he struggles like Kagawa and Mikhi does. Hence the price. Is the news today not that we offered £89m and Dortmund rejected that and want £120m?
Maximin I say would suit the league more physically only as I've watched Newcastle a lot and he dribbles like Mane, with pace and power and direction, and that's hard to defend against. His end product is nowhere near Sancho's, but from what I've seen he has a footballing brain so it can be improved.