I found that despite of all these tools, my PC took no performance hit from the use of Norton. Until I wanted to use it, I didn't even notice it was there.
OS X protection
Norton One: OS XClick to view larger image.
Norton Internet Security for the Mac (which works with OS X Lion or later) offers a full suite of security software, but it doesn't include most of the extras in the PC version, such as system performance tools and System Insight.
So you get anti-virus, firewall and Norton Identity, which blocks phishing sites. There's also a File Guard feature that blocks changes to files and stops files from being accessed if personal information might be compromised.
All of the features are available from a single icon at the top of the screen. Click it and a drop-down list appears; you can then choose the security feature you want to customize or run. The anti-virus features lets you select individual folders of files to scan, do a quick scan of all your files, or do a more comprehensive system scan. You can set the scan to ignore certain files and folders. The firewall also allows for a good deal of customization.
Generally, though, Norton Internet Security for the Mac is a set-and-forget piece of software. Install it, use the defaults, and you'll be protected.
Norton One: AndroidClick to view larger image.
Norton One's Android security software, Norton Mobile Security, protects Android devices against a wide variety of threats.
You can scan for malware manually or on a daily, weekly or monthly schedule. You can also scan your SD card, which is vital for Android users who have moved apps to their SD cards.
The anti-theft feature is especially well done. You create a password, and if you lose your phone or it's stolen, you can send a text message to it from any phone with the word "lock" followed by your password. That will lock the phone, and it can only be unlocked when your password is entered.
If you download a free add-on, you can also locate your device by going to the Norton Anti-Theft website; from there, you can remotely trigger your device's camera to take a photo, which may help you in finding the device or identifying a thief.
However, you can't lock your device remotely from the Web -- only from another phone -- so your only choice for remote lock is sending text message, which is far from ideal. This is something that should be fixed.