From an operational flexibility standpoint, the MP5N model is probably a better bet. It's got a removable suppressor, telescoping stock and simple single, full auto and safe selector. You can use +p+ ammo without the suppressor and subsonic with it. You can also mount a suppressor on the MP5/10 model and get trigger kits and the rest to mimick the MP5N, plus you get the power of the 10mm Auto cartridge, which is a HUGE step up from the 9mm NATO.
In real world use, the SMG is being eclipsed by the M4 carbine. Strange as it seems, the 5.56mm round fired from the M4 is less prone to overpenetration of both bodies and building materials than the 9mm round thanks to violent fragmentation at CQB ranges. You can also suppress the M4 nicely. It won't be as quiet as the MP5SD series which is scary quiet, but it'll definitely make shooting the 5.56mm NATO round a lot more comfortable in closed quarters.