I personally use Bitdefender Antivirus Plus 2016, which is the cheapest paid antivirus they sell. I decided to go for a paid antivirus software due to the absolutely ridiculous marketing that AVG, Avira, and surprisingly Avast were throwing at me to buy their products. I did about 30 whole minutes of research and found that any form of paid Bitdefender was ALWAYS in the top three out of at least 10 to 25 different AV programs tested. I have had no issues with Bitdefender on Windows 10 Pro, and the added functionality of a paid software will always beat the basic functionality of free software. Do not use AVG because in the last year or two they have turned into adware, not antivirus software. Avast is pretty decent if you pay for it, but I found its UI to be relatively un-intuitive and sometimes overly complicated with a marginally high learning curve. Avira was really simple, but despite this it felt like it was too simple and that made it seem like it wasn't offering much protection. I want an antivirus software that has the ability to schedule scans, tells me exactly where issues are found, offers good encryption options, has good support, and is very fairly priced for the quality of protection you receive. Bitdefender is the only option, and I highly recommend its paid version. Unless you have extremely sensitive or classified materials on your computer, I suggest you just get the regular paid version. No issues in the past several months, and it catches everything.