Tottenham have recently signed players mostly from Serie A, half of their Starting XI come from Italy (Udogie, Vicario, Kulusevski, Bentancur, Romero) and they're well above Manchester United in the league, playing much more entertaining football.
The fact all Tottenham signings from Serie A have been successful while MUFC's ones all bad make me think that maybe the problem is not the quality of the leagues where you buy from.
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That said, I follow Atalanta of course given I'm italian and Ederson has been very good so far this season.
I'd say he's been top5 midfielder in the league and overall better than that highly rated Koopmeiners guy so, to me, he would be very good signing for Manchester United if the price stay around £30-40m