Know-How Exchange : Social Media

My agency is going through the process of finding a social media management tool that fits our needs the best. We have a high volume of clients which we provide "launch" social media programs for—we update and manage their social media accounts (Facebook, Twitter and Pinterest) for three months. After the three month period, we provide a metrics report and recommendations, including a proposal to extend their services (6/12 mo. social media management plan).

At this time, we have 90 clients associated with this side of our business and will have ~35-45 active on social at any given time. Due to this high volume, we need a tool that accommodates many clients, while providing metric reports for each client and basic listening. We have found many tools that support multiple clients but fail to provide the additional things we need, such as a metrics report for each within the plan.

I currently stand here:
- Pinterest - Viraltag; 1 account only supports 5 Pinterest profiles so we would need multiple Viraltag accounts for our clients. Is there a better, economical option?
- Facebook and Twitter - HootSuite: Able to have 50 clients on one Pro plan (supporting both FB and Twitter), but do not receive a metrics report for all clients (each report is additional cost).

Are there one or two tools that can support the needs listed above better than HootSuite and Viraltag? Advice is much appreciated.

Thank you!