So you are at the crossroads trying to decide whom to approach for building your mobile app. The idea of an agency sounds good and you might also want to try working with a freelancer for App development services. Below are few ideas that will help you decide what might work best for you.
Working with agencies is easy since they recruit staff after a lot of pre-screening and have competent work-force. Whereas freelancers are hired solely based on the communication and online tests which cannot be relied upon.