For the past 2 1/2 years I've used BitDefender, which has had a good reputation.
Three weeks ago, I had a virus attack (while browsing using Google Chrome) that disabled BitDefender, as in, the program would not start, would not reinstall.
Every time I re-booted, a seemingly random file opened. After 5 minutes, a popup diagnosing an infection would open, and, shortly, a "scan" would start. After 10 minutes, Windows-resembling error messages with red X's would appear and something would try to install itself.
I contacted "Support", attaching (to save time - hahahaha!) two diagnostic tests I knew would be the first thing they'd ask for. One week later, after several emails, "Support" sent me two more diagnostic programs to run, which I did, and returned the results. Ten days later (now) and still no response. My last two messages have been demands for a refund.
They have a phone "Support" line as well, you know. Twice I was placed on automatic hold "due to the high volume." I listened to elevator music for 15 minutes, then the connection went dead. Twice.
I'm not alone.
PC Tools Spyware Doctor with Antivirus
UPDATE: 25 days and counting from the time BitDefender was notified that a virus had disabled their product - 25 days without a solution!
UPDATE: June 21! 30 days with no recommendation from BitDefender. A truly pathetic Support department. Don't buy BitDefender.
UPDATE #3: June 24. BitDefender finally responded, apologizing for the delay and saying they've corrected the issues. So I suppose it's "safe" to buy BitDefender again, as long as you don't mind a 33-day delay in answering if you have problems.