When people barter, they tend to bloat their prices, so they can receive more. Years ago a printer wanted to trade with me. Their proposition was that they would give me a run of business cards and I would write them a sales letter.
First of all the reputation of the IT services and support a company offers should be checked thoroughly. When you have a problem you'll want it solved as soon as possible, saving time, disruption and money. The internet is full of reviews of these companies and in order to check them it's easy to log-in on Google, type managed it services and support company reviews and get a list with dozens of results to check out.
Hands-on tech support I.T service is expensive to provide long term. Hint: Dell, HP and eMachine are investing millions in low-cost "over the phone" help desk support. They are not hiring as many "boots on the ground" technicians as before. This means that when you do get a problem that requires a little hands-on work, you go on a long waiting list.
How many customers does this leave unhappy. Even one is too many. By all means have your tech team help out with internal Managed I.T support uttah. issues, but only after all customer facing issues have been resolved. In the meantime an outsourced support team can do the grunt work for the rest of your staff.
The problem is that far too many business owners call in external help too late. Just imagine. What is the point in hiring the best ship consultants to save your sinking ship after she hit an iceberg and is already 9/10 under water?
At the very least, you'll find leads that you can investigate. Sometimes the very first one will do the trick! If the first one doesn't fix the problem, go back to the results page and try another lead. Many, many times I have been able to figure out the problem this way, and it's extremely satisfying, not to mention way faster than the alternatives.