Managed application and end-user support from a team that learns your environment and stays, with service levels agreed up front and reported every month.
Tickets close faster when the person answering knows how your systems connect. Our support teams stay on your account, so the fix for last month's problem is still in someone's head, not only in a knowledge base.
A team asks the same question before and after IT Support and Helpdesk is in place. The answer depends on whether the people answering know your environment.
The problem was solved before. The knowledge left with the last team.
Same issue, same users. The difference is a team that remembers.