In the simplest terms, the two key ingredients for a successful MSP are signing new clients and retaining them. New competitors are entering the MSP landscape every day as VAR's are attracted to the recurring revenue stream.
Don’t look now, but you can be sure those competitors are targeting your customers with offers to deliver more value for less cost. According to this Charted Institute of Marketing study, "it costs between 4 and 10 times more to acquire a new customer than it does to keep an existing one."