There are three types of metrics that you want to collect.

1) Aggregate metrics
2) Cohort metrics
3) Funnel metrics

A tool like Flurry is OK for aggregate metrics. Google Analytics for mobile is probably the better choice depending on your needs.

For cohort and funnel metrics, I prefer using Mixpanel. And for tracking App installs I prefer Tapstream.

For a deeper dive into the above analytics types above, I recommend reading Lean Analytics by Alistair Croll and Ben Yoskovitz.