The name is only an ingredient of your success. If you are relying on the name to make your service successful you have a recipe for failure. If everything is

The name is only an ingredient of your success. If you are relying on the name to make your service successful you have a recipe for failure. If everything is perfect (interface, design, backup/recovery,scalability) and the name is the cherry on top go for it. If you have any doubts and will need those resources to fix issues or get you past "the hump" wait and launch with a different domain. As you said you can buy it later at a higher price but at least you will have cash flow.