Pros: I own several sites, and after an algorithm update set me back on a couple of them, I decided to be proactive and get ahead of problems. Screaming Frog was kinda a no brainer... so many other digital marketers I know are using it to audit their sites regularly. My experience so far has been mixed, but I would say positive rather than negative. There are things I love about it... The in-depth audits, the sitemap facility, and the fact that it automates a lot of stuff that would otherwise take too much time to do manually. There are definitely things I feel can be better. The UI is a bit cluttered, and it can take a while to get used to. Also, if you don't change default server settings you may experience problems during high traffic periods. The other thing I think they can improve is ability to crawl big sites. The bigger a site is, the more hitches you experience with regular site audits.