Because we needed one Personally i'm using: - Webroot SA mobile - Adguard for Mobile - Lastpass (since it becomes free now)
1st I want to say I don't notice any slowdowns or problems with my setup. YMMV don't root if you're a novice. Unless you study at XDA & accept you might Brick your phone, otherwise don't tweak. Been the same setup except AVs for 2yrs. LG D950 rooted. AFWall+, DisableService, Malwarebytes, & MinMinGuard.
I'm using: 1) Avast (free) for antivirus & firewall - runs real-time. On-demand, Avast runs full scans & (if you tell it to) will also clean up apps that have been closed but are still lingering in the background, using RAM. This is also free. Avast offers some other stuff that is NOT free. I haven't tried any of that yet. 2) MBAM (free) for second opinion full scans, on-demand. (It offers to run real-time, but I gave that job to Avast). 3) LastPass for password management (free, however => keep reading). For online surfing, LastPass does this job via its built-in Chrome-based browser. It will also do passwords for other apps, if you ask it to (settings). It's PRO-status for 60 days. After that, if you want to retain PRO capabilities, it costs $$. If you don't go PRO, then LastPass will continue to work for you -- minus some functions. I haven't researched to see which functions will go away, & how much the PRO costs. I'll worry about that whenever. ~~~~~~~~~~~~~ By the way, Zemana Anti-Malware (ZAM) has recently begun offering a version for phone/tablet computers. I use ZAM on my desktop computer & love it. It's lighter than MBAM & does an = or > job (so I've heard), but I'll stick with MBAM for a while. ~~~~~~~~~~~~ The ability to regularly IMAGE my system disk is a key ingredient of the security for my desktop computer. I haven't found any such capability for phone/tablet computers. If you know of one, please share.
Kaspersky and AdGuard w/Firewall LastPass for my password management No negative effect on Android whatsoever, only positive.
ZAM lifetime (because screw it, why not?) LastPass (You don't need to use their browser, you can use the notification shade and your browser of choice) AdGuard Lifetime license
CyanogenMod with: AFWall+ ARP Guard Network Connection iShredder Enterprise NakedBrowser Pro Camera Block Microphone Block MyAndroidTools
I've found that SD Maid often finds more junk than other cleaners, and I've used many different cleaners.