I was looking for a lightweight app which would block calls based on my own manually maintained blacklist. This app does exactly what I need, and actually much more, (like blocking SMS based on many criteria, scheduled blocking, etc), but it definitely cannot be called a bloatware. Functions you do not need can be simply turned off. No annoyances, no ads, just reliable service. Moreover, I am impressed by it's small footprint, just 0,2 MB. Running on Android 4.1.1. Heartly recommend it.