Best App Downloads?

In your experience who has given you the best bang for your buck when it comes to app installs?
I'm currently starting with appbrain + mylikes both on 20-50$ test runs. Anyone have any past experience with either?

I'm trying to scale the downloads up on my first app, so I'm really open minded on where to look next.

I can provide google play app installs -- normal retention
I can also provide ios app installs + ratings + reviews
Competitive rates
Pm me on Skype: Ekoch1997