I'm using the free version of AVG Mobilation and it works great. It's a silent app and it only shows notifications if you install or update any app wherein it scans the installed or updated applications. Same goes for scheduled scans if you have any. It also has a Web protection, SMS scanning and Anti-Theft feature.
When researching a mobile security app for my new android phone after elimination Norton and Lookout it came down to AVG and Avast.
Avast won the day for me after taking everything into totality, functions, battery drain(AVG having the least) ,cost, reviews from experts and other users, ect.