Choose a host who understands your specific needs, and who can sit down with you and talk about what your needs are, and how that host can accommodate those needs.
The virtual private server is the happy medium between the two alternatives. The server is partitioned and your company is afforded an entire one of the partitions. However, since the server is partitioned, other users on the server do not affect you in the same way as they might on a shared server.
I can advise you to compare all web hosting services, as it is a top priority for your new web host business to be well-provided with all necessary tools.