Donnarumma is the best GK out of those but Lammens is a smart purchase on the same level of us getting Trafford. Both are young with potential to grow into great keepers. Onana is a bum, shame they replaced him.
If you read the BBC article on Lammens, he is a world beater at his age. What they forgot to really mention throughout the article and his stats, until pretty much the end of the article, even though it’s blindly obvious, was those stats were achieved in the Belgium league. Let’s see how he performs in the PL over a season. He will be in goals for United in the derby, that’s for sure.
He made the most saves of any keeper in Europe's top 10 leagues last season (173) and at an 80% save percentage. He was second only to Anderlecht's Colin Coosemans for goals prevented last season too.
His on-ball quality, however, is relatively untested given the Belgian opposition faced don't press as intensely as the forwards in the Premier League. Lammens opts to play long under pressure and places it in general areas his team-mates are in. His short passing is generally safe but not a stand-out quality at present.
Etc.
Senne Lammens transfer: Why Man Utd signed Belgian and not Emiliano Martinez
Why Manchester United have signed Belgian goalkeeper Senne Lammens and what it reveals about their future ambitions.