While not terribly slow, I changed from my ISP's DNS servers to the Google ones because they occasionally don't work. When they work they are pretty fast. Howev

While not terribly slow, I changed from my ISP's DNS servers to the Google ones because they occasionally don't work. When they work they are pretty fast. However, from time to time they were unresponsive. Sometimes that didn't happen for days, and sometimes they were unresponsive for 30-second bursts several times an hour, and then you couldn't browse the web or check your email. I changed to 8.8.8.8 and waited to see if that was the problem. Since I changed the problem hasn't reappeared, so I keep using 8.8.8.8. I'm no friend of giving Google all my data, but the privacy policy on their DNS servers is quite clear. They don't use the data to correlate it with anything and only cache it for some times for technical reasons, whiping it afterwards. It's fair and doesn't redirect you for failed queries.