The .NET/C# driver is showing slower insert performance for an insert of 100 documents when compared to the node driver. Tested against Atlas M0. 

Node.js insert 100 documents: 28 ms
Node.js read 100 documents: 22 ms
Node.js delete 100 documents: 24 ms

C# insert 100 documents: 848 ms
C# read 100 documents: 27 ms
C# delete 100 documents: 24 ms

Here is the code I used for testing:
C# Driver: v3.3
Node.js Driver: v6.15

Reported in forums post here.