Just looked at your supplier.
I do see the Antec 300: Komplett.ie - Antec Three Hundred Midi Tower Black
As an aside, case gurus seem to think very highly of the Antec Solo: Komplett.ie - Antec Solo Miditower, Piano
A bit cheaper than the 900.
The Solo gets quite high marks for being a quiet case.
Too many openings in a case is often just a way for noise to escape. Cases often run just as cool with fewer holes if the fans are appropriate. I personally would avoid vents on the top side.
If noise typically does not bother you, then go with your first choice. Antec generally gets high marks, but some are quieter than others.