The MP5SD is, function-wise, very similar to its other MP5 counterparts. It does have the benefit of having an integral suppressor, but not suffering from the attachment's damage penalty if the target is shot within 28 meters compared to the regular MP5.
Overall, the submachine gun is suited for more close-quarters engagements, where its benefits shine. It has a better damage output compared to the MP5, and has the angled grip option available. It's recoil is manageable but slightly harder than the regular MP5 due to the lack of recoil-altering muzzle attachments. The submachine gun's integral suppressor functions like a normal suppressor.