I'm not all that thrilled about them because the make me complete captchas all the dame time just because I like to route my browsing through Tor. I'd understand if I was running scrapers or other high-intensity requests through tor exit nodes, but usually I'm just loading pages at slow intervals to actually read the content. I guess it's like news sites that piss and moan about my adblocker on my very first visit before I've had a chance to actually evaluate any of their content (and I do whitelist sites I visit even semi-regularly).