In-house super or as-need service?

[Achi Adamit]

I'm curious to know if anyone who owns either small multi family or large ones uses their own in-house supers or a service to send out supers on an as need basis.

If you use a service, how do they charge, and are you happy with them?

I know that in North Jersey where I am, there is at least one such service that I can think of.

Also, what are the pros and cons of each? 

Any advice would help me in deciding which direction to go. Thanks in advance!