Kaspersky recieved a 99.7% detection rate result from the AV Comparitives Mobile Security Review behind only AhnLab and Kingsoft. From AV Test, Kaspersky recieved a 6/6 in both protection and usability.
Kaspersky is not the most lightweight application or as well optimized as applications such as Lookout. Some slowdowns may be experienced using Kaspersky but that may be a necessary sacrifice for Kaspersky's stronger virus detection rate.
Lookout is a lightweight application that has a small influence on device performance such as start up times and battery life. Although when downloading applications there is a slight slow down because Lookout will scan every application.
Safe browsing (a feature that scans every link and site you visit), privacy advisor (manages and explains application permissions), remote lock, remote wipe, enhanced backup, and a few other features are reserved for premium users only. Fortunately though for antivirus purposes Lookout premium is...