Based on the introductions of each one, you can definitely find out which of the two will fit your needs for the task at hand. Both are made available to our MSPs so that they can go as ‘lite’ (PM) as they want with C1 or go ‘fully-featured’ (ITSM) if they need to do more than patching on their client’s devices.
We do recommend to you use ITSM Patch Management functionality since ITSM is planned to be the center for all endpoint operations. We are going to remove (old) stand alone Patch Management module from the C1 portfolio in the near future to avoid confusion.