Probably the first question to address when deciding on a development vendor is whether to go with a large, established firm or a smaller shop. A large firm may have robust resources and an excellent reputation, but its important to understand whether a large firm will give you the attention that you need. On the other hand, is a small shop going to have the experience and resources you’re looking for? They may offer the degree of attention you require, but attention itself is insufficient if they lack the expertise related to your industry.
When reviewing development vendors, look at the resources that are actually building your venture. Will a larger firm outsource the coding and programming to the lowest level employees and simply use its size and expertise in a project management capacity? At a smaller firm, it could be the case where the partners themselves will be involved in the development of your idea. This type of hands-on approach may speed up development, though it could also lead to a small firm being overwhelmed, as they’ve taken on more than they can chew.